Multi-user multi-touch projected capacitance touch sensor with event initiation based on common touch entity detection

ABSTRACT

Techniques for providing multi-user multi-touch projected capacitive touch sensors are disclosed herein. Some embodiments may include a method that includes receiving a first sense signal from a first sensing array, the first sensing array configured to provide the first sense signal indicating a first touch on a first touch surface of a touch substrate as well as receiving a second sense signal from a second sensing array, the second sensing array configured to provide the second sense signal indicating a second touch on a second touch surface of a second touch substrate occurring concurrently to the first touch. The method may further include determining whether the first touch and the second touch share at least one anti-ghost. The method may also include associating the first touch and the second touch with a common touch entity in response to determining that the first touch and the second touch share the at least one anti-ghost.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Nonprovisional patentapplication Ser. No. 17/504,827, titled “MULTI-USER MULTI-TOUCHPROJECTED CAPACITANCE TOUCH SENSOR WITH EVENT INITIATION BASED ON COMMONTOUCH ENTITY DETECTION,” filed Oct. 19, 2021, which is a continuation ofU.S. Nonprovisional patent application Ser. No. 16/868,932, titled“MULTI-USER MULTI-TOUCH PROJECTED CAPACITANCE TOUCH SENSOR WITH EVENTINITIATION BASED ON COMMON TOUCH ENTITY DETECTION,” filed May 7, 2020,which is a continuation of Ser. No. 16/195,212, titled “MULTI-USERMULTI-TOUCH PROJECTED CAPACITANCE TOUCH SENSOR,” filed Nov. 19, 2018,which is a continuation of U.S. Nonprovisional patent application Ser.No. 15/470,040, titled “MULTI-USER MULTI-TOUCH PROJECTED CAPACITANCETOUCH SENSOR,” filed Mar. 27, 2017, which is a continuation of U.S.Nonprovisional patent application Ser. No. 15/076,100, filed Mar. 21,2016, titled “MULTI-USER MULTI-TOUCH PROJECTED CAPACITANCE TOUCHSENSOR,” which is a continuation of U.S. Nonprovisional patentapplication Ser. No. 14/322,605, filed Jul. 2, 2014, titled “MULTI-USERMULTI-TOUCH PROJECTED CAPACITANCE TOUCH SENSOR,” which claims thebenefit of U.S. Provisional Patent Application No. 61/843,850, filedJul. 8, 2013, titled “APPARATUS AND METHODS FOR MULTI-USER MULTI-TOUCHPROJECTED CAPACITANCE TOUCH SENSOR,” all of which are herebyincorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION Field of the Invention

Embodiments of the invention relate, generally, to touch sensorsincluding multi-user multi-touch functionality.

Background Art

Projected capacitive touch (PCAP) technology uses electric fields fromembedded electrodes projected through glass layers that are influencedby finger touches with the result of changes in measured capacitances.For example, at each “point” or intersection of embedded electrodes, adistinct mutual capacitance change due to touch activity can be measuredor “addressed.” PCAP touch sensors are currently found in portabledevices such as smartphones, tablets, laptops, etc. and are configuredto receive multiple concurrent touches from a single person to enablemulti-touch functionality.

BRIEF SUMMARY OF THE INVENTION

Embodiments to improve touch sensors are described herein. Someembodiments may provide for a method. The method may include receiving afirst sense signal from a first sensing array, the first sensing arrayconfigured to provide the first sense signal indicating a first touch ona first touch surface of a touch substrate. The method may also includereceiving a second sense signal from a second sensing array, the secondsensing array configured to provide the second sense signal indicating asecond touch on a second touch surface of a second touch substrateoccurring concurrently to the first touch. Based on the first sensesignal and second sense signal, the method may further includedetermining whether the first touch and the second touch share at leastone anti-ghost. Furthermore, the method may include associating thefirst touch and the second touch with a common touch entity in responseto determining that the first touch and the second touch share the atleast one anti-ghost.

Some embodiments may include a system including a memory and at leastone processor coupled to the memory. The processor may be configured toreceive a first sense signal from a first sensing array, the firstsensing array configured to provide the first sense signal indicating afirst touch on a first touch surface of a touch substrate. The processormay further be configured to receive a second sense signal from a secondsensing array, the second sensing array configured to provide the secondsense signal indicating a second touch on a second touch surface of asecond touch substrate occurring concurrently to the first touch. Basedon the first sense signal and second sense signal, the processor may befurther configured to determine whether the first touch and the secondtouch share at least one anti-ghost. The processor may further beconfigured to associate the first touch and the second touch with acommon touch entity in response to determining that the first touch andthe second touch share the at least one anti-ghost.

Some embodiments may include a non-transitory, tangible,computer-readable medium configured to implement the methods and/orother functionality discussed herein. For example, the non-transitory,tangible, computer-readable medium may have instructions stored thereonthat, when executed by at least one computing device, causes the atleast one computing device to implement the functionality discussedherein.

These as well as additional features, functions, and details of variousembodiments are described below. Similarly, corresponding and additionalembodiments are also described below.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

Having thus described various embodiments in general terms, referencewill now be made to the accompanying drawings, which are not necessarilydrawn to scale, and wherein:

FIG. 1 shows an example touch sensor in accordance with someembodiments;

FIG. 2 shows an example touch sensor receiving a touch in accordancewith some embodiments;

FIG. 3 shows an example sense signal data matrix including a touch inaccordance with some embodiments;

FIG. 4 shows an example touch sensor receiving two touches in accordancewith some embodiments;

FIG. 5 shows an example sense signal data matrix including two touchesin accordance with some embodiments;

FIG. 6 shows an example touch sensor receiving two touches from a commontouch entity in accordance with some embodiments;

FIG. 7 shows an example sense signal data matrix receiving two touchesfrom a common touch entity in accordance with some embodiments;

FIGS. 8A and 8B show example sense signal data plots in accordance withsome embodiments;

FIG. 9 shows an example method for providing multi-user multi-touchfunctionality on a touch sensor based on anti-ghosts performed inaccordance with some embodiments;

FIG. 10 shows an example method for determining (e.g., physical,electrically conductive) contact between individual users based onanti-ghosts performed in accordance with some embodiments;

FIG. 11 shows an example touch sensor receiving two touches along asensing axis in accordance with some embodiments;

FIG. 12 shows an example sense signal data matrix including two touchesalong a sensing axis in accordance with some embodiments;

FIG. 13 shows an example sense signal data matrix including two touchesalong a second sensing axis in accordance with some embodiments;

FIG. 14 shows an example method for providing multi-user multi-touchfunctionality based on continuity of anti-ghosts performed in accordancewith some embodiments;

FIG. 15 shows an example method for providing multi-user multi-touchfunctionality based on signal strength of touches performed inaccordance with some embodiments;

FIGS. 16A and 16B show example sense signal strength data plots inaccordance with some embodiments;

FIG. 17 shows an example touch sensor in accordance with someembodiments;

FIG. 18 shows an example touch sensor in accordance with someembodiments;

FIG. 19 shows an example method for providing multi-user multi-touchfunctionality based on one axis anti-ghost measurements performed inaccordance with some embodiments;

FIGS. 20A and 20B show an example sensing array for determining one axisanti-ghosts in accordance with some embodiments;

FIG. 21 shows an example XYU sensing array in accordance with someembodiments;

FIG. 22 shows an example XYU touch sensor in accordance with someembodiments;

FIG. 23 shows an example XYUV sensing array in accordance with someembodiments;

FIG. 24 shows an example XY sensing array including polygonal electrodesin accordance with some embodiments;

FIG. 25 shows an example XUV sensing array in accordance with someembodiments;

FIG. 26 shows an example single layer bridge of the XUV sensing arrayshown in FIG. 25 in accordance with some embodiments;

FIG. 27 shows an example method for manufacturing a single layer bridgeperformed in accordance with some embodiments;

FIG. 28 shows an example of an XYUV sensing array in accordance withsome embodiments;

FIG. 29 shows an example single layer bridge of the XYUV sensing arrayshown in FIG. 28 in accordance with some embodiments;

FIG. 30 shows an example cross sectional view of the XYUV sensing arrayshown in FIG. 28 in accordance with some embodiments;

FIG. 31 shows an example top electrode substrate layer of an XYUVsensing array in accordance with some embodiments;

FIG. 32 shows an example XYUV sensing array including the top electrodesubstrate layer of FIG. 31 in accordance with some embodiments;

FIG. 33 shows an example XYUV sensing array in accordance with someembodiments;

FIG. 34 shows the XYUV sensing array of FIG. 33 in accordance with someembodiments;

FIG. 35 show example conductive meshes in accordance with someembodiments;

FIG. 36 shows a cross sectional view of an example XYUV sensing arrayincluding conductive meshes shown in FIG. 35 in accordance with someembodiments;

FIGS. 37A and 37B show example interactive digital signage in accordancewith some embodiments;

FIG. 38 shows an example computing device in accordance with someembodiments; and

FIG. 39 shows an example interactive digital signage in accordance withsome embodiments.

FIGS. 40A and 40B show example sense signal data plots from multipletouch sensors in accordance with some embodiments.

FIG. 41 shows an example method for providing multi-user multi-touchfunctionality using multiple touch sensors based on anti-ghosts inaccordance with some embodiments.

FIG. 42 shows an example method for responding to multi-user multi-touchinteractions between multiple touch entities in accordance with someembodiments.

FIG. 43 shows an example method for providing multi-user multi-touchfunctionality for non-concurrent touches in accordance with someembodiments.

FIG. 44 shows an example computing device that includes a touch sensorduring multiple states in accordance with some embodiments.

FIGS. 45A-45C show example sensing arrays in accordance with someembodiments.

FIG. 46 is an example computer system useful for implementing variousembodiments.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments will be described more fully hereinafter with reference tothe accompanying drawings, in which some, but not all embodimentscontemplated herein are shown. Indeed, various embodiments may beimplemented in many different forms and should not be construed aslimited to the embodiments set forth herein; rather, these embodimentsare provided so that this disclosure will satisfy applicable legalrequirements. Like numbers refer to like elements throughout.

Some embodiments may provide for a projected capacitive (PCAP) touchsensor that supports multi-touch functionality for multiple users at thesame time. For multiple touches occurring concurrently, the touch sensormay be configured to determine touches that belong to a common touchentity and initiate a common touch entity interaction mode accordinglyfor those touches. The touch sensor may also determine that touchesbelong to different touch entities and may initiate a multi-touch entityinteraction mode. For example, in the multi-touch entity interactionmode, multiple common touch entity interaction modes may be initiatedfor two or more users concurrently.

FIG. 1 shows an example projected capacitive touch sensor 100 (“touchsensor 100”) in accordance with some embodiments. Touch sensor 100 mayinclude touch substrate 102, sensing array 104, signal generator 106,and controller 108.

Touch substrate 102 may be formed of optically transparent material(s),including a laminated stack of transparent materials (such as shown inFIG. 30 ), capable of propagating electromagnetic fields generated bysensing array 104. Touch substrate 102 may include touch surface 110 forreceiving one or more touches (e.g., concurrently).

Sensing array 104 may define a plurality of sensing axes of touch sensor100. For example, sensing array 104 may include X axis electrodes thatdefine an X sensing axis and Y axis electrodes that define a Y sensingaxis. The X and Y sensing axes are example reference axis that may beused for touch detection, although other (e.g., arbitrary) sensing axesmay be used. In some embodiments, electrodes associated with a sensingaxis may be oriented perpendicular to the sensing axis direction so thata signal associated with an electrode corresponds to a more-or-less welldefined value of the sensing axis coordinate. Where two (e.g.,perpendicular and/or otherwise intersecting) sensing axes are used,touch sensor 100 may be referred to herein as an “XY touch sensor.” Invarious other embodiments, sensing array 104 may define more than twosensing axes, such as XYU (e.g., 3), XYUV (e.g., 4), or more sensingaxes. Here “sensing” in “sensing axis” may refer to a reference axis forsensing touches and does not necessarily a connection with sensing(e.g., vs. drive) electronics.

Sensing array 104 may include Y axis electrodes 112 a, 112 b, 112 c and112 d (sometimes referred to herein collectively as “electrodes 112”)and X axis electrodes 114 a, 114 b and 114 c (sometimes referred toherein collectively as “electrodes 114”). For example, each ofelectrodes 112 and 114 can be line-shaped electrodes that individuallyspan across sensing axes. Other electrode shapes and arrangements may beused, some examples of which are discussed in greater detail below. Insome embodiments, sensing array 104 may include one or more electrodesubstrate layers, such one or more layers of glass or a polymer materialsuch as Polyethylene terephthalate (PET) (e.g., substrate layer 116), onwhich sensing array 104 may be formed (e.g., of indium tin oxide (ITO)).In FIG. 1 , only a small number of electrodes 112 and 114 are shown toavoid unnecessarily overcomplicating the disclosure, although sensingarray 104 may include more or less electrodes (e.g., depending on size,touch resolution, etc. of the touch sensor).

Sensing array 104 may be configured to provide sense signals indicatingone or more touches, such as to controller 108 and/or other senseelectronics. Sensing array 104 may be configured to receive inputsignals from signal generator 106, which in various embodiments, may beincluded within controller 108 and/or may be implemented in driveelectronics separate from controller 108 (e.g., as shown in FIG. 1 ).For example, via control of selectable switch 120, signal generator 106may be configured to selectively send the input signals via input lines118 a, 118 b, 118 c and 118 d to each of Y axis electrodes 112 a, 112 b,112 c and 112 d, respectively. With reference to the shown embodiment, Yaxis electrodes 112 a, 112 b, 112 c and 112 d may operate in a drivemode and be referred to as “drive electrodes.”

Sensing array 104, via X axis electrodes 114, may be configured togenerate sense signals for touch determination. For example, X axiselectrodes 114 a, 114 b and 114 c may be configured to send the sensesignals to controller 108 and/or other sense electronics via outputlines 122 a, 122 b and 122 c. Here, X axis electrodes 114 may operate ina sense mode and be referred to as “sense electrodes.” For example, Xaxis electrodes 114 may be conductively isolated from Y axis electrodes112 such that a mutual capacitance may be formed between Y axiselectrodes 112 and Y axis electrodes 114. Furthermore, upon receivingthe input signals, Y axis electrodes 112 may configured to generateelectromagnetic fields that propagate through touch substrate 102 andinteract with one or more touches on touch surface 110 of touchsubstrate 102. In particular, a touch may cause a detected decrease inmutual capacitance between at least one drive electrode and at least onesense electrode that is present in the sense signals (e.g., as comparedwith a baseline mutual capacitance between drive and sense electrodes inthe absence of a touch), which may be interpreted as a touch locationcontroller 108.

Controller 108 may include circuitry (e.g., one or more processors)configured to execute firmware and/or software programs stored in one ormore memory devices to perform the functionality disclosed herein forproviding multi-user multi-touch functionality. In some embodiments,controller 108 may interface with a computer system, such as a personalcomputer, interactive digital signage, multi-user device (e.g., amulti-player gaming table), embedded system, kiosk, user terminal,and/or other machine as a human-to-machine interface device. Thecomputer system may include a main controller with one or moreprocessors configured to execute firmware and/or software programsstored in one or more memory devices. Via the execution of the programs,the computer system may generate a visual component (and/or displayelement) that is sent to a display device for display. The visualcomponent may include a user interface that is operable using the touchsensor. In various embodiments, controller 108 may be implemented onseparate or the same hardware as main controller.

FIG. 2 shows an example touch sensor 100 including a touch in accordancewith some embodiments. Touch sensor 100 (e.g., via touch surface 110)may be configured to detect one or more touches, such as touch 202.Touch 202 may be a detectable altering of the electrical properties oftouch sensor 100, which may result from a touch entity, such as from afinger of a person, making contact with touch sensor 100. In someembodiments, touch 202 may be detected when a stylus or other pointingapparatus touches touch sensor 100. The touch entity is shown in FIG. 2as being represented by touch entity circuit equivalent 204. Touchentity circuit equivalent 204 may include ground capacitor 206, groundswitch 208 and ground 210. Generally, ground capacitor 206 may representa capacitance between the touch entity and ground 210. If the touchentity is a user standing in front of touch sensor 100, a contributionto the ground capacitor 206 may be from the proximity of the user's feetto a concrete pad under a floor with the soles of the user's shoes and acarpet on the floor acting as an insulating gap in the ground capacitor206. The numerical value of capacitance of ground capacitor 206 mayvary. For example, if the touch entity is a user who initially iswearing thin soled shoes, and then switches to wearing thick platformshoes made of an insulating material, the numerical value of capacitanceof ground capacitor 206 will decrease. When the touch entity isthoroughly grounded (e.g., standing in a puddle of water and/or wearinga grounded anti-static wrist strap), there is a direct connection toground that may be represented by a closed switch 208.

FIG. 3 shows an example sense signal data matrix 300 in accordance withsome embodiments. In some embodiments, touch sensor 100 may beconfigured to operate sensing cycles for touch detection. Within asensing cycle, sense signals may be generated that include sense signaldata represented by sense signal data matrix 300. In this example, asensing cycle may represent a “snapshot” of touch activity on touchsensor 100 within a finite duration of time that may appearinstantaneous to the touch entity.

With reference to FIGS. 2 and 3 , during a sensing cycle, senseelectrodes 114 a, 114 b and 114 c may be placed in the sense mode forgenerating the sense signals. Each drive electrode may selectively(e.g., via switch 120) receive input signals from signal generator 106.For example, drive electrode 112 a may receive the input signal viainput line 118 a and drive electrodes 112 b, 112 c and 112 d may beinactivated (e.g., not being driven with an input signal). Mutualcapacitances between drive electrode 112 a and each of sense electrodes114 a, 114 b and 114 c may be represented in sense signals and sent tocontroller 108 via output lines 122 a, 122 b and 122 c, respectively.Because there is no touch on touch surface 110 corresponding with thelocation of drive electrode 112 a (e.g., touch 202 is at a locationcorresponding only with drive electrode 118 d), each of the sensesignals on output lines 122 a, 122 b and 122 c may represent thebaseline mutual capacitance, as shown by blank entries 122 a-114 a, 122a-114 b and 122 a-114 c within sense signal data matrix 300.

During the same sensing cycle, drive electrode 112 b may next receivethe input signal via input line 118 b and drive electrodes 112 a, 112 cand 112 d may be inactivated. Mutual capacitances between driveelectrode 112 b and each of sense electrodes 114 a, 114 b and 114 c maybe represented in sense signals and sent to controller 108 via outputlines 122 a, 122 b and 122 c, respectively. Because there is no touch ontouch surface 110 corresponding with the location of drive electrode 112b, each of the sense signals on output lines 122 a, 122 b and 122 c mayrepresent the baseline mutual capacitance, as shown by blank entries 122b-114 a, 122 b-114 b and 122 b-114 c within sense signal data matrix300.

During the same sensing cycle, drive electrode 112 c may next receivethe input signal via input line 118 c and drive electrodes 112 a, 112 band 112 d may be inactivated. Mutual capacitances between driveelectrode 112 c and each of sense electrodes 114 a, 114 b and 114 c maybe represented in sense signals and sent to controller 108 via outputlines 122 a, 122 b and 122 c, respectively. Because there is no touch ontouch surface 110 corresponding with the location of drive electrode 112c, each of the sense signals on output lines 122 a, 122 b and 122 c mayrepresent the baseline mutual capacitance, as shown by blank entries 122c-114 a, 122 c-114 b and 122 c-114 c within sense signal data matrix300.

During the same sensing cycle, drive electrode 112 d may next receivethe input signal via input line 118 d and drive electrodes 112 a, 112 band 112 c may be inactivated. Mutual capacitances between driveelectrode 112 d and each of sense electrodes 114 a, 114 b and 114 c maybe represented in sense signals and sent to controller 108 via outputlines 122 a, 122 b and 122 c, respectively. Because touch 202 is presenton the portion of touch surface 110 corresponding with the location ofdrive electrode 112 d and sense electrode 114 b, the sense signals onoutput line 122 b may represent a mutual capacitance that is less thanthe baseline mutual capacitance, as shown by “T” entry 112 d-114 bwithin sense signal data matrix 300. For example, touch entity circuitequivalent 208 may act as an extension of drive electrode 112 c thatpulls some of the electrical energy from sensing array 104 to ground210, thereby decreasing mutual capacitance between drive electrode 112 cand sense electrode 112 b from the baseline mutual capacitance. Becausetouch 202 is not present on touch surface 110 at locations correspondingwith sense electrodes 114 a and 114 c, each of the sense signals onoutput lines 122 a and 122 c may represent the baseline mutualcapacitance, as shown by blank entries 112 d-114 a and 112 d-114 cwithin sense signal data matrix 300. Depending on sensing array design,a touch, such as touch 202, may result in multiple non-zero entries suchas weak signals in entries 112 d-114 a, 112 c-114 b and 112 d-114 c aswell as a strong touch signal in entry 112 d-114 b. In some embodiments,such secondary weaker signals may be used to provide greater precisionin touch location determinations. Nevertheless, for clarity ofpresentation, such weak secondary signals are neglected in FIG. 3 (andsimilar FIGS. 5 and 7 ).

FIG. 4 shows an example touch sensor 100 including two touches fromdifferent touch entities in accordance with some embodiments. Touch 202may be generated by a first touch entity that is the same touch entityas discussed above and shown in FIG. 2 . Touch 402 may be generated by asecond touch entity different from the touch entity that generated touch202. For example, touch 202 may be generated by a finger of a firstperson and touch 402 may be generated by a finger of a second person. Assuch, touch 402 is shown in FIG. 4 as represented by touch entitycircuit equivalent 404 including ground capacitor 406, ground switch408, and ground 410. Touch 202 and 402 may be generated from differenttouch entities that are not touching each other or otherwise inelectrically conductive contact, except perhaps with a common ground viagrounds 210 and 410. The discussion above regarding touch entity circuitequivalent 204 may be applicable to touch entity circuit equivalent 204.

FIG. 5 shows an example sense signal data matrix 500 in accordance withsome embodiments. Within a sensing cycle, sense signals may be generatedthat include sense signal data represented by sense signal data matrix500. For example, because touch 402 is also present on touch surface 110corresponding with the location of drive electrode 112 a and senseelectrode 114 c, the sense signals on output line 122 c may represent amutual capacitance that differs from (e.g., is less than) the baselinemutual capacitance, as shown by “T” entry 112 a-114 c within sensesignal data matrix 300. As such, one or more (e.g., concurrent) touchesmay be detected by touch sensor 100, such as within the same sensingcycle.

Multi-User Multi-Touch Based on Anti-Ghosts

FIG. 6 shows an example touch sensor 100 including two touches from acommon touch entity in accordance with some embodiments. As discussed ingreater detail below, as a result of the design of the sensing array,touch 602 and touch 612 may share one or more anti-ghosts when generatedfrom the common touch entity. For example, touch 602 and touch 612 maybe determined to be associated with a common touch entity when touch 602and touch 612 share at least one anti-ghost. Touch 602 and touch 612would have been associated with different touch entities had an absenceof a common anti-ghost been detected (e.g., as shown by the entries ofsense signal data matrix 500).

A touch entity, as used herein, may refer to an individual person and/ortwo or more people in electrically conductive contact with each other.For example, touch 602 and touch 612 may be generated by a first fingerand a second finger, respectively, of an individual person. In anotherexample, touch 602 and touch 612 may be generated by a first finger of afirst person and a second finger of a second person where the people aretouching each other or otherwise in electrically conductive contact. Ineither case, the touch entity generating touches 602 and 612 may berepresented by touch entity circuit equivalent 604. Touch entityequivalent circuit 604 may include ground capacitor 606, ground switch608, connection 614, and ground 610. The discussion above regardingtouch entity circuit equivalent 204 may be applicable to touch entityequivalent circuit 604. Furthermore, connection 614 may provideelectrical conduction between touches 602 and 612 via the touch entity.For example, connection 614 may represent an electrical connectionbetween a first finger (e.g., generating touch 602) and a second finger(e.g., generating touch 612) through the hand/body where the touchentity is an individual. In another example, connection 614 mayrepresent an electrical connection between a finger of a first personand a finger of a second person through the bodies of the first andsecond people where the touch entity includes the first and secondperson.

FIG. 7 shows an example sense signal data matrix 700 in accordance withsome embodiments. Sense signal data matrix 700 may represent sensingsignal data generated by touch sensor 100 in response to two touchesfrom a common touch entity. With reference to FIGS. 6 and 7 , a sensingcycle may be initiated similar to the sensing cycle described above withreference to FIGS. 2 and 3 . For example, sense electrodes 114 a, 114 band 114 c may be placed in the sense mode for generating the sensesignals. Drive electrode 112 a may receive the input signal via inputline 118 a and drive electrodes 112 b, 112 c and 112 d may beinactivated. Mutual capacitances between drive electrode 112 a and eachof sense electrodes 114 a, 114 b and 114 c may be represented in sensesignals and sent to controller 108 via output lines 122 a, 122 b and 122c, respectively. Because touch 612 is present on touch surface 110corresponding with the location of drive electrode 112 a and senseelectrode 114 c, the sense signals on output line 122 c may represent amutual capacitance that is less than the baseline mutual capacitance, asshown by “T” entry 112 a-114 c within sense signal data matrix 700.However, unlike in FIG. 4 (e.g., for separate touches 202 and 402),electrical energy may also flow from drive electrode 112 a through thetouch entity via connection 614 to sense electrode 114 b (e.g., at touch602), thereby increasing the mutual capacitance of sense electrode 114 bfrom the baseline mutual capacitance. The increase in mutual capacitancecaused by connection 614 may be determined to be an anti-ghost, as shownby “A” entry 112 d-114 b within sense signal data matrix 700. Note thatthere is physically no touch at the intersection of electrodes 112 a and114 b, so the change in measured mutual capacitance at entry 112 a-114 bis an artifact or “ghost.” The “anti” in the lexicon “anti-ghost” ischosen to highlight the fact that this signal artifact of increasedmeasured mutual capacitance is opposite in algebraic sign from decreasedmutual capacitance measured at true touch locations. In someembodiments, such as depending on design of sensing arrays, electronics,etc., anti-ghosts may be of decreased mutual capacitance while truetouches may be of increased mutual capacitance.

During the same sensing cycle, drive electrode 112 d may receive theinput signal via input line 118 d and drive electrodes 112 a, 112 b and112 c may be inactivated. Mutual capacitances between drive electrode112 d and each of sense electrodes 114 a, 114 b and 114 c may berepresented in sense signals and sent to controller 108 via output lines122 a, 122 b and 122 c, respectively. Because touch 602 is present ontouch surface 110 corresponding with the location of drive electrode 112d and sense electrode 114 b, the sense signals on output line 122 b mayrepresent a mutual capacitance that is less than the baseline mutualcapacitance, as shown by “T” entry 112 d-114 b within sense signal datamatrix 700. However, unlike in FIG. 4 (e.g., for separate touches 202and 402), electrical energy may also flow through the touch entity viaconnection 614 to sense electrode 114 c, thereby increasing the mutualcapacitance of sense electrode 114 c from the baseline mutualcapacitance. The increase in mutual capacitance caused by connection 614may be determined to be an anti-ghost, as shown by “A” entry 112 d-114 cwithin sense signal data matrix 700.

FIGS. 8A and 8B show example sense signal data plots 800 and 850,respectively, in accordance with some embodiments. Like FIGS. 3, 5 and 7, FIGS. 8A and 8B represent tables of entries corresponding tointersections between drive and sense electrodes. However, signal dataplots 800 and 850 more explicitly represent an embodiment where thenumber of electrodes of a sensing array is large (e.g. 100 driveelectrodes 112 and 200 sense electrodes 114). For clarity ofpresentation, FIGS. 8A and 8B is not shown as numerous small entry boxesas in FIGS. 3, 5 and 7 , but rather represent electrodes 112 as aquasi-continuous horizontal axis and electrodes 114 as aquasi-continuous vertical axis. Sense signal data plots 800 and 850 maybe generated based on the sense signal data received from sensing array104, such as during a sensing cycle. Sense signal plots 800 and 850 mayinclude background 802 representing the baseline mutual capacitancebetween drive and sense electrodes. Touches 802, 804 and 806 may begenerated by a first touch entity (e.g., touch entity A) and mayrepresent mutual capacitance values less than the baseline mutualcapacitance. Similarly, touches 808 and 810 may be generated by a secondtouch entity (e.g., touch entity B) and may also represent mutualcapacitance values less than the baseline mutual capacitance.

Because touches 802, 804 and 806 are from a common touch entity (e.g.,touch entity A), circuitry discussed herein can be configured to detectan anti-ghost associated with any two pairs of touches 802, 804 and 806.Upon detecting an anti-ghost associated with a pair of touches from thesense signals received from the sensing array, the circuitry may befurther configured to determine that pair of touches “share” ananti-ghost. For example, anti-ghosts 812 and 814 may be determined to beshared by touches 804 and 806, anti-ghosts 816 and 818 may be determinedto be shared by touches 802 and 804, and anti-ghosts 820 and 822 may bedetermined to be shared by touches 802 and 806. Similarly, becausetouches 808 and 810 are from a common touch entity (e.g., touch entityB), anti-ghosts 824 and 826 may be determined to be shared by touches808 and 810. As shown in FIG. 8B, anti-ghosts may be detected atintersections of projections of two touches of a touch entity alongsensing axis directions (e.g., the X and Y sensing axis). For example,anti-ghost 818 may be detected at the intersection of the projection oftouch 802 along the X sensing axis and the projection of touch 804 alongthe Y sensing axis. Similarly, anti-ghost 816 may be detected at theintersection of the projection of touch 802 along the Y sensing axisdirection and the projection of touch 804 along the X sensing axisdirection.

As shown in sense signal data plot 850, two touches from different touchentities do not share anti-ghosts. For example, no anti-ghost may bedetected at intersections 828 and 830 of projections along sensing axesof touch 802 (from touch entity A) and projections along sensing axes oftouch 808 (from touch entity B).

FIG. 9 shows an example method 900 for providing multi-user multi-touchfunctionality on a touch sensor based on anti-ghosts performed inaccordance with some embodiments. Method 900 may be performed toleverage the anti-ghost effect discussed above. In some embodiments,method 900 may be performed by a controller and/or other suitablyconfigured circuitry, such as controller 108 of touch sensor 100 shownin FIG. 1 .

Method 900 may begin at 902 and proceed to 904, where the controller maybe configured to receive sense signals from a sensing array. The sensesignals may indicate a first touch and a second touch occurringconcurrently on a touch surface of a touch substrate, such as touchsurface 110 of touch substrate 102 of touch sensor 100. In someembodiments, the sense signals may represent sense signal data acquiredduring sensing cycles of touch sensor 100. As such, the first touch andthe second touch may occur “concurrently” on the touch surface whenpresent during a single sensing cycle. For example, the first touch andthe second touch may first occur (e.g., begin) simultaneously and may bemaintained for the single sensing cycle. Furthermore, the first touchand the second touch may occur “concurrently” despite beginning atseparate times. For example, the first touch may occur (e.g. begin)prior to the second touch and may be maintained on the touch surfacesuch that the first touch is concurrent with the second touch (e.g., forthe single sensing cycle).

At 906, the controller may be configured to determine whether the firsttouch and the second touch share at least one anti-ghost based on thesense signals. For example, and as discussed above in connection withFIGS. 6-8B (e.g., touches 602 and 612 of FIG. 6 ), the controller may beconfigured to determine that the first touch and the second touch sharethe at least one anti-ghost when the at least one anti-ghost is presentat an intersection of projections of the first touch and the secondtouch along sensing axes of the touch controller (e.g., as defined bysensing array 102). Similarly, the controller may be configured todetermine that the first touch and the second touch fail to share the atleast one anti-ghost when no anti-ghost is present at any intersectionsof the first touch and the second touch along sensing axes of the touchcontroller (e.g., touches 202 and 204 of FIG. 4 and as shown by thesense signal data matrix 500 in FIG. 5 ).

In response to the controller determining that the first touch and thesecond touch share the at least one anti-ghost, method 900 may proceedto 908, where the controller may be configured to associate the firsttouch and the second touch with a common touch entity. As discussedabove, the common touch entity may be an individual person or may be twoor more people in electrically conductive contact.

At 910, the controller may be configured to enable a common touch entityinteraction mode. For example, the first touch and the second touch maybe used to determine a multi-touch capability of touch controller 110such as pinch to zoom, two-finger scrolling, secondary select, and/orany other suitable multi-touch input. Method 900 may then proceed to 912and end.

Returning to 906, in response to determining that the first touch andthe second touch fail to share the at least one anti-ghost (e.g., do notshare any anti-ghosts), method 900 may proceed to 914, where thecontroller may be configured to associate the first touch with a firsttouch entity and the second touch with a second touch entity differentfrom the first touch entity. For example, the first touch entity may bea first person and the second touch entity may be a second person.

At 916, the controller may be configured to enable a multipletouch-entity interaction mode. For example, the first touch and thesecond touch may each be used to determine separate single touchcapability of touch controller 110. Although method 900 is discussedwith respect to two touches, it is appreciated that more than twotouches may be detected in the sense signals. For example, a third touchmay be detected and share at least one anti-ghost with the first touchand no anti-ghosts with the second touch. Here, common touch entityinteraction mode may be enabled for the first and third touch andmultiple touch-entity interaction mode be enabled for the second touchand the combination of the first touch and the third touch. In thatsense, a multiple touch-entity interaction mode may include two or moreseparate common touch entity interaction modes. Method 900 may then endat 912.

FIG. 10 shows an example method 1000 for determining contact betweenindividual users based on anti-ghosts performed in accordance with someembodiments. Method 1000 may be performed to leverage the fact thatanti-ghosts may also be generated when two or more individual peoplemake electrically conductive contact (e.g., touching each other whilealso concurrently touch the touch sensor). In some embodiments, method1000 may be performed by a controller and/or other suitably configuredcircuitry, such as controller 108 of touch sensor 100 shown in FIG. 1 .

Method 1000 may begin at 1002 and proceed to 1004, where the controllermay be configured to receive sense signals from a sensing array, thesense signals indicating a first touch and a second touch occurringconcurrently at a touch surface of a substrate. The discussion above at904 of method 900 may be applicable at 1004.

At 1006, the controller may be configured to determine that at least oneanti-ghost that was undetected in the sense signals when the first touchand the second touch were first detected. For example, the determinationat 906 of method 900 may be performed in a first sensing cycle when thefirst touch and the second touch are initially detected. Here, the firsttouch and the second touch may be determined to fail to share the atleast one ant-ghost, indicating that the first touch and the secondtouch are associated with different touch entities when the first touchand the second touch were first detected. At 1008, the controller may beconfigured to associate the first touch with a first touch entity andthe second touch with a second touch entity different from the firsttouch entity.

At 1010, the controller may be configured to determine whether the firsttouch and the second touch share at least one anti-ghost. For example,the first touch and the second touch may be maintained on the touchsensor following the first sensing cycle, such as for several sensingcycles including a second sensing cycle. In the second sensing cycle,the determination at 906 of method 900 may be repeated.

In response to determining that the first touch and the second touchshare the at least one anti-ghost, method 1000 may proceed to 1012,where the controller may be configured associate to the first touch andthe second touch with a common touch entity, wherein the common touchentity is a first person and a second person in electrically conductivecontact. For example, the first person and the second person may havemade electrically conductive contact with each other causing the atleast one anti-ghost to appear that was not present when the firstperson and the second person were not in electrically conductive contactat 1006. In some embodiments, a multi-user common touch entityinteraction mode may be enabled. For example, the multi-user commontouch entity interaction mode may allow the touch sensor to provideinputs (e.g., to a main controller, application, operating system,device, etc.) indicating whether or not users of the common touch entityare touching each other.

At 1014, the controller may be configured to determine a contact timebetween the first person and the second person based on when theanti-ghost first become detected in the sense signals. For example, thecontact time may indicate when the first person and the second personcame into electrically conductive contact. Method 1000 may then end at1016.

Returning to 1010, in response to determining that the first and secondtouch fail to share the at least one anti-ghost, method 1000 may proceedto 1018, where the controller may be configured to continue to associatethe with the first touch entity and the second touch with the secondtouch entity. As discussed above at 916 of method 900, the controllermay further be configured to initiate a multiple touch-entityinteraction mode. Method 1000 may then proceed to 1016 and end.

For simplicity and clarity of presentation, the example flow chart ofFIG. 10 does not show all the iterative loops that may be present insome embodiments. For example, after it has been determined at 1018 thatfirst and second touch entities are not yet in electrical contact,method 1000 may iteratively loop back to decision step 1010 (e.g., manytimes) until contact is made and method 1000 may proceed to 1012.Furthermore, method 1000 may be generalized to recognize not only theinitiation of electrical contact between two users, but also thebreaking of such electrical contact. Hence, in some embodiments, thecontroller may be configured to associate the first touch with the firsttouch entity and the second touch with the second touch entity upondisappearance of a shared anti-ghost. For example, in response todetermining a shared anti-ghost disappeared after being detected asbeing shared by the first touch and the second touch, the controller maybe configured to detect that a first person and a second persondiscontinued electrically conductive contact with each other.Furthermore, the controller may be configured to determine a releasetime and/or initiate a multi-touch entity interaction mode.

Anti-Ghost Overlap

The discussion above regarding anti-ghosts and when they are detectedmay not always be applicable, such as when an anti-ghost overlaps (e.g.,in location) with a touch. For example, an overlapping anti-ghost mayoccur when a first touch and a second touch are located along a commonsensing axis (e.g., share a common X or Y coordinate on an XY touchsensor). FIG. 11 shows an example touch sensor 100 including two touchesfrom a common touch entity along a common sensing axis in accordancewith some embodiments. The discussion above regarding touch entitycircuit equivalent 604 of FIG. 6 may be applicable to touch entitycircuit equivalent 1102. Unlike touches 602 and 612 in FIG. 6 , however,in some embodiments touches 1104 and 1106 are both along sense electrode114 c that defines (e.g., along with the other sense electrodes) the Xsensing axis. As such, touches 1104 and 1106 are along the common Xsensing axis.

FIG. 12 shows an example sense signal data matrix 1200 in accordancewith some embodiments. Sense signal data matrix 1200 may representsensing signal data generated in a sensing cycle by touch sensor 100 inresponse to two concurrent touches from a common touch entity along acommon sensing axis, as shown in FIG. 11 (e.g., for touches 1104 and1106 along the common X sensing axis defined by sense electrode 114 c).As shown in sense signal data matrix 1200, no anti-ghosts are readilypresent despite the fact that touches 1104 and 1106 are generated by thesame touch entity because touches 1104 and 1106 are along a commonsensing axis. Because anti-ghost signals “A” are generally smaller inmagnitude than touch signals “T”, an overlapping anti-ghost “A” andtouch signal “T” may appear as a touch signal “T” with a somewhatreduced signal magnitude.

For example, sensing cycles may be performed as discussed above. Senseelectrodes 114 a, 114 b and 114 c may be placed in the sense mode forgenerating the sense signals. Drive electrode 112 a may receive theinput signal via input line 118 a and drive electrodes 112 b, 112 c and112 d may be inactivated. Because touch 1106 is detected on touchsurface 110 corresponding with the location of drive electrode 112 a andsense electrode 114 c, the sense signals on output line 122 c mayrepresent a mutual capacitance that is less than the baseline mutualcapacitance, as shown by “T” entry 112 a-114 c within sense signal datamatrix 1200. Circuitry may also drive electrical energy from driveelectrode 112 a through the touch entity via connection 1108 to senseelectrode 114 c at touch 1104, thereby increasing the mutual capacitancedetected at sense electrode 114 c relative to the reduced mutualcapacitance that would have resulted from touch 1106 alone. In someembodiments, the magnitude of the measured mutual capacitance decreasefrom touch 1106 may be much larger than the increase in measured mutualcapacitance from the anti-ghost effect resulting from connection 1108and touch 1104. Here, the net effect may be a decreased measured mutualcapacitance, or a “T”, for entry 112 a-114 c despite the contributionfrom the anti-ghost effect.

Similarly, the increase in mutual capacitance caused by connection 1108does not cause an anti-ghost at entry 112 a-114 c within sense signaldata matrix 1200, because touch 1104 is also present and overlapping, asshown by “T” entry 112 d-114 c within sense signal data matrix 1200. Forexample, within the same sensing cycle, drive electrode 112 d mayreceive the input signal via input line 118 d and drive electrodes 112a, 112 b and 112 c may be inactivated. Because touch 1104 is present ontouch surface 110 corresponding with the location of drive electrode 112d and sense electrode 114 c, the sense signals on output line 122 c mayrepresent a mutual capacitance that is less than the baseline mutualcapacitance, as shown by “T” entry 112 a-114 c within sense signal datamatrix 1200. Electrical energy may also be driven from drive electrode112 d through the touch entity via connection 1108 to sense electrode114 c at touch 1106, thereby increasing the detected mutual capacitanceof sense electrode 114 c relative to the reduced mutual capacitance thatwould have resulted from touch 1104 alone. The net effect is still adecreased measured mutual capacitance despite the contribution from theanti-ghost effect. Hence, the increase in mutual capacitance caused byconnection 1108 does not cause an anti-ghost at entry 112 a-114 c withinsense signal data matrix 1200 because overlapping touch 1106 is alsopresent.

As discussed in greater detail with respect to FIGS. 15-16B, theincrease in mutual capacitance caused by connection 1108 at entries 112a-114 c and 112 a-114 b may represent a smaller signal strength effectthan the decrease in mutual capacitance caused by touches 1104 and 1106.As such, when a detected touch overlaps with an expected anti-ghost, thetouch may be readily detected based on the sense signals while (e.g.,overlapping) anti-ghosts are less readily apparent (e.g., despitetouches 1104 and 1106 being generated by the common touch entity), asshown in sense signal data matrix 1200.

FIG. 13 shows an example sense signal data matrix 1300 in accordancewith some embodiments. Sense signal data matrix 1300 may representsensing signal data generated by touch sensor 100 (e.g., in a sensingcycle) in response to detecting two concurrent touches from a commontouch entity along a second common sensing axis direction (e.g., the Xsensing axis direction). For example, “T” entries 112 a-114 a and 112a-114 c may each represent a detected touch along the common X sensingaxis direction parallel to Y drive electrode 112 a. For reasons similarto those described in connection with FIGS. 11 and 12 , two or moretouches along the X sensing axis direction may also be readily detectedbased on the sense signals while (e.g., overlapping) anti-ghosts areless readily apparent (e.g., despite the touches being generated by thecommon touch entity), as shown in sense signal data matrix 1300.

Example techniques for detecting overlapping anti-ghosts and, thus,addressing the anti-ghost overlap problems are discussed below. Sometechniques may include modifications to controller configurations, thesensing array configurations, and/or sensing electronics configurations.In some embodiments, one or more of the techniques discussed herein maybe implemented and/or techniques not explicated discussed herein (e.g.,depending on the use requirements of touch controller 100).

FIG. 14 shows an example method 1400 for providing multi-usermulti-touch functionality based on monitoring continuity of anti-ghosts.In some embodiments, method 1400 may be performed to, at leastpartially, detect anti-ghosts that may occur at the same location as adetected touch. For example, method 1400 can be executed to determinewhether a second touch belongs to the same touch entity as the firsttouch when two touches of a common touch entity are not along a commonsensing axis (e.g., no anti-ghost overlap initially) when the twotouches first become concurrent on the touch surface. In someembodiments, method 1400 may be performed by a controller and/or othersuitably configured circuitry, such as controller 108 of touch sensor100 shown in FIG. 1 .

Method 1400 may begin at 1402 and proceed to 1404, where the controllermay be configured to associate the first touch and the second touch witha common touch entity based on detecting the first touch, the secondtouch, and at least one anti-ghost generated by the sensor, and thendetermining the first touch and the second touch share the at least oneanti-ghost. The discussion at 908 of method 900 may be applicable at1404.

At 1406, the controller may be configured to determine a disappearancetime for the at least one anti-ghost indicating a length of time thatthe anti-ghost disappeared while the first touch and the second touchremained detected. For example, the anti-ghost may be determined to havedisappeared from the sense signals in a subsequent sensing cycle after asensing cycle where the at least one anti-ghost was detected. In someembodiments, the disappearance time may be measured beginning at thedisappearance of the at least one anti-ghost and ending at thereappearance of the at least one anti-ghost while the first touch andthe second touch remained detected throughout.

At 1408, the controller may be configured to determine whether thedisappearance time exceeds a continuity threshold. The continuitythreshold may represent a predetermined length of time in which thecontroller may treat disappearance of the at least one anti-ghost asbeing caused by temporary anti-ghost overlap of moving touches. Thecontinuity threshold may be measured using any suitable means, includinga counter, sensor cycles, and/or processor clock cycles.

In response to determining that the disappearance time fails to exceedthe continuity threshold, method 1400 may proceed to 1410, where thecontroller may be configured to continue to associate the first touchand the second touch with the common touch entity within thedisappearance time. In some embodiments, temporary disappearance of theat least one anti-ghost may not effect operation of the touch sensorand/or the multi-user mode being implemented. For example, the touchsensor may continue to operate in the common touch entity interactionmode. Method 1400 may then end at 1412. Alternatively or additionally,pairs of touches previously identified as due to a common touch entitymay continue indefinitely to be regarded as due to the common touchentity as long as the overlap condition exists (e.g., for which a lackof anti-ghosts is consistent with both common and separate touch entityinterpretations of signals). In some embodiments, a pair of touchesassociated with a common touch entity may be re-interpreted as due toseparate touch entities either when a time exceeds a continuitythreshold, or when the overlap condition ends without the appearance ofanti-ghosts, whichever occurs first.

Returning to 1408, in response to determining that the disappearancetime exceeds the continuity threshold, method 1400 may proceed to 1414,where the controller may be configured to associate the first touch witha first touch entity and the second touch with a second touch entitydifferent from the first touch entity within the disappearance time.Alternatively and/or additionally, the controller may be configured todetermine that the first touch entity and the second touch entity lostelectrically conductive contact during the disappearance time, such aswhen the common touch entity determined at 1404 includes multipleindividual people corresponding with the first touch entity and thesecond touch entity at 1414. Method 1400 may then proceed to 1412 andend.

FIG. 15 shows an example method 1500 for providing multi-usermulti-touch functionality based on signal strength of touches performedin accordance with some embodiments. Method 1500 may be performed to, atleast partially, resolve the detection of touches associated with thesame touch entity despite not detecting anti-ghosts due to theanti-ghosts overlapping with the touches. For example, method 1500 maybe helpful when a first touch occurs prior to a second touch and ismaintained on the touch surface such that the first touch is concurrentwith the second touch. Independent of whether there is a potentialanti-ghost overlap or not, the method 1500 may be performed to determinewhether or not the second touch belongs to the same touch entity as thefirst touch. In that sense, method 1500 may be performed in response tothe second touch being determined as being along a common sensing axisdirection as the first touch and/or when the first touch occurs prior tothe second touch regardless of whether the first touch and the secondtouch are along a common sensing axis. In some embodiments, like othermethods discussed herein, method 1500 may be performed by a controllerand/or other suitably configured circuitry, such as controller 108 oftouch sensor 100 shown in FIG. 1 .

Method 1500 may begin at 1502 and proceed to 1504, where the controllermay be configured to determine that a first touch occurs prior (in time)to a second touch's initial occurrence, and the first touch ismaintained on the touch surface such that the first touch is concurrentwith the second touch. For example, where sensing cycles are used, thefirst touch may be detected and the second touch may be undetected inthe sense signals in a first sensing cycle. In a subsequent sensingcycle, the first touch may be detected again (e.g., maintained throughmultiple sensing cycles in some embodiments) concurrently with thesecond touch.

At 1506, the controller may be configured to determine whetheroccurrence of the second touch coincided with a signal strength drop ofthe first touch. FIGS. 16A and 16B show example sense signal strengthdata plots 1600 and 1650, respectively, in accordance with someembodiments. In plots 1600 and 1650, “Z” represents the detected signalstrength of a touch and is plotted along vertical axis 1602 againsttime, which is plotted along horizontal axis 1604. As shown in plot 1600of FIG. 16A, first touch 1606 occurs at time T₁ prior to second touch1608, which occurs at time T₂. Also at time T₂, signal strength Z₁ offirst touch 1606 drops ΔZ₁ to signal strength Z₁′. Here, occurrence ofthe second touch may be determined to have coincided with a signalstrength drop for the first touch due to the processor detecting theoverlapping anti-ghost with the first touch. Plots 1600 and 1650 showsignal strengths for first touch 1606 and second touch 1608 relative tothemselves over time, but not necessarily with respect to each other(e.g., Z₁ is not necessarily greater than Z₂ as shown).

As shown in plot 1650 of FIG. 16B, first touch 1606 also occurs at timeT₁ prior to second touch 1608, which occurs at time T₂. However, at timeT₂, signal strength Z₁ of first touch 1606 does not drop to lower signalstrength. Here, occurrence of the second touch may be determined to havefailed to coincide with a signal strength drop for the first touch.

In some embodiments, a coinciding signal strength drop for the firsttouch may indicate that placement of the second touch has caused theprocessor to detect a shared anti-ghost that overlaps with the firsttouch on the sensing array. As discussed above, a touch may cause adetected decrease in mutual capacitance and an anti-ghost may cause adetected increase in mutual capacitance, albeit at a smaller magnitude.As such, when the first touch overlaps with an anti-ghost shared by thefirst touch and the second touch, the circuitry may detect theanti-ghost and be configured to determine its presence based on analgorithm associated with the relative timing of a signal strength drop(e.g., ΔZ₁), such as when the timing of the first touch is determined tohave coincided with the occurrence of the second touch. Thus thedetection of a signal strength drop (e.g., ΔZ₁) provides a means ofanti-ghost detection even when a true touch overlaps the position of theanti-ghost.

In response to determining, for example, that the occurrence of thesecond touch coincided with a signal strength drop associated with thefirst touch, method 1506 may proceed to 1508, where the controller maybe configured to associate the first touch and the second touch with acommon touch entity based on the first touch and the second touchsharing at least one detected anti-ghost, wherein the presence of theanti-ghost is extrapolated based on the relative timing of the firsttouch's signal strength drop. The discussion at 908 of method 900 may beapplicable at 1508. Method 1500 may then proceed to 1510 and end.

In response to determining that the occurrence of the second touchfailed to coincide with a signal strength drop for the first touch,method 1506 may proceed to 1512, where the controller may be configuredto associate the first touch with a first touch entity and the secondtouch with a second touch entity different from the first touch entity.In this regard, there may still be a signal strength drop, but thatsignal strength drop may not be associated with an overlappinganti-ghost, because the timing of the signal strength drop did notsufficiently coincide (in time, clock cycles, and/or signature) with thesecond touch. The discussion at 914 of method 900 may be applicable at1512. Method 1500 may then proceed to 1510 and end.

In some embodiments, touches are detected on projected capacitivesystems through both mutual capacitance measurements (as describedabove) as well as self-capacitive measurements. Detection of changes in,or anomalous values of, the ratio of mutual-capacitance signal toself-capacitive signal for a touch may also be used in algorithms fordetermining whether or not two touches are from the same or differenttouch entities.

FIG. 17 shows an example touch sensor 100 in accordance with someembodiments. Here, touch sensor 100 as shown in FIG. 1 is shown inschematic plan view. Touch sensor 100 may include sensing array 104,drive electronics 1702, and sense electronics 1704. As discussed abovein connection with FIG. 1 , sensing array 104 may define two sensingaxes, and in that sense, touch sensor 100 may be an example of an XYtouch sensor. In particular, Y axis electrodes 112 may define the Ysensing axis and X axis electrodes 114 may define the X sensing axis.

Drive electronics 1702 may be configured to generate input signals todrive each of Y axis electrodes 112, and as such, Y axis electrodes 112may operate in a drive mode as drive electrodes. In some embodiments,drive electronics 1702 may include signal generator 106 and switch 120,or the like. For example, in a sense cycle, drive electronics 1702 maybe configured to send the input signal from signal generator 106 to eachof Y axis electrodes 112 (e.g., one at a time). Sense electronics 1704may be configured to set X axis electrodes 114 to a sense mode (e.g.,connect to current or charge sensing virtual grounds) for detectingmutual capacitances associated with touches and/or anti-ghosts. In someembodiments, drive electronics 1702 and/or sense electronics 1704 mayimplemented via a controller or other suitable circuitry, such ascontroller 108 shown in FIG. 1 .

FIG. 18 shows an example touch sensor 1800 including drive and senseelectrodes in accordance with some embodiments. Touch sensor 1800 mayinclude sensing array 1802, including Y axis electrodes 1804 and X axiselectrodes 1806. Touch sensor 1800 may further include drive and senseelectronics 1808 and drive and sense electronics 1810.

Drive and sense electronics 1808 and 1810 may be configured toselectively perform both drive and sense functions, such as thosedescribed herein for drive electronics 1702 and sense electronics 1704in FIG. 17 . As such, both Y axis electrodes 1804 and X axis electrodes1806 may selectively operate in the drive mode and the sense mode asdrive and sense electrodes. In some embodiments, drive and senseelectronics 1808 and/or 1810 may include one or more multiplexers forselecting between operation in the drive mode and sense mode for thedrive and sense electrodes. In some embodiments, drive and senseelectronics 1808 and/or 1810 may be implemented via a controller orother suitable circuitry, such as controller 108 shown in FIG. 1 .

FIG. 19 shows an example method 1900 for providing multi-usermulti-touch functionality based on one axis anti-ghosts measurementsperformed in accordance with some embodiments. Method 1900 may beperformed with touch sensors including drive and sense electronicsand/or drive and sense electrodes, such as touch sensor 1800 shown inFIG. 18 , to detect and/or otherwise resolve overlapping anti-ghosts andtouches (e.g., to determine whether two touches along a sensing axis aregenerated by a common touch entity or different touch entities).

Method 1900 may begin at 1902 and proceed to 1904, where a controller ofa touch sensor (e.g., touch sensor 1800) may be configured to receivesense signals from a sensing array. The sense signals may indicate afirst touch and a second touch occurring concurrently on a touch surfaceof a touch substrate. The discussion above at 904 of method 900 may beapplicable at 1904.

At 1906, the controller may be configured to determine whether the firsttouch and the second touch occurred along a sensing axis defined by thesensing array. As discussed above in connection with FIGS. 11-13 , thefirst touch and the second touch may be detected and, thus, determinedto have occurred along a sensing axis based on the sense signalsreceived from the sensing array. In an example where the touch sensor isan XY touch sensor, the first touch and the second touch may bedetermined to have occurred along the X sensing axis (e.g., as shown inFIG. 13 ) or the Y sensing axis (e.g., as shown in FIG. 12 ). Similarly,for an XYU touch sensor, the first touch and the second touch may bedetermined to have occurred along a sensing axis when the first touchand the second touch occurred along any of the X, Y or U sensing axis.

In response to determining that the first touch and the second touchoccurred along a sensing axis defined by the sensing array, method 1900may proceed to 1908, where the controller may be configured to determinewhether the first touch and the second touch share a one axisanti-ghost. For example, the controller may be configured to determinewhether an anti-ghost signal exists between the first touch and thesecond touch by using sensing electrodes of one axis only. FIGS. 20A and20B show an example sensing array 1802 for determining one axisanti-ghosts in accordance with some embodiments. Sensing array 1802 mayinclude Y axis electrodes 1804 and X axis electrodes 1806 that define Xand Y sensing axis. After first touch 2002 (e.g., at coordinates (X1,Y1)) and second touch 2004 (e.g., at coordinates (X2, Y1)) aredetermined as having occurred along the X sensing axis direction (e.g.,as detected at 1906 by switching Y axis electrodes 1804 to the drivemode and X axis electrodes 1806 to the sense mode, or vice versa), thecontroller and/or drive and sense electronics may be configured tooperate a one axis anti-ghost sensing cycle for the X axis electrodes.The one axis anti-ghost sensing cycle may be performed to make one-axisanti-ghost measurements, among other things.

For example, the one axis anti-ghost sensing cycle may include switchingX axis electrode 1806 a (e.g., corresponding with X1 of first touch2002) to the drive mode and switching X axis electrode 1806 b to thesense mode. As shown in FIG. 20A, when touches 2002 and 2004 are from acommon touch entity, electrical energy may flow via connection 2006(e.g., the hand/body of an individual person) from drive electrode 1806a to sense electrode 1806 b. For example, the controller may beconfigured to determine that detected touches 2002 and 2004 share a oneaxis anti-ghost. As electrodes 1806 a and 1806 b are parallel and neverintersect, the corresponding one axis anti-ghost differs from theanti-ghosts indicated in FIGS. 7, 8A and 8B in having no obviousplan-view geometrical location. Nevertheless, such one axis anti-ghostsmay still provide information with which to associate or separate pairsof touches.

As shown in FIG. 20B, when touches 2002 and 2004 are from differenttouch entities, and hence lacking connection 2006, the sensor will beunable to drive energy from drive electrode 1806 a to sense electrode1806 b during the one axis anti-ghost sensing cycle. Because no energyis driven along this path, the circuitry can be configured to determinethat touches 2002 and 2004 fail to share a one axis anti-ghost.

Additionally or alternatively, in response to determining the firsttouch and the second touch occurred along the same X sensing axis, thecontroller and/or drive and sense electronics may be configured tooperate a one axis anti-ghost sensing cycle for the Y axis electrodes todetermine whether there is an one-axis anti-ghost that the first touchand the second touch share.

Returning to FIG. 19 , in response to determining that the first touchand the second touch share the one axis anti-ghost at 1908, method 1900may proceed to 1910, where the controller may be configured to associatethe first touch and the second touch with the common touch entity. Thediscussion above at 908 of method 900 may be applicable at 1910. Method1900 may then proceed to 1912 and end.

In response to determining that the first touch and the second touchfail to share the one axis anti-ghost at 1908, method 1900 may proceedto 1914, where the controller may be configured to associate the firsttouch with a first touch entity and the second touch with a second touchentity different from the first touch entity. Additionally oralternatively, like any method discussed herein, the controller and/orother circuitry could be configured to execute another method fordetecting overlapping anti-ghosts before determining that the touchesare associated with the same and/or different touch entities. Thediscussion above at 914 of method 900 may be applicable at 1914. Method1900 may then proceed to 1912 and end.

Returning to 1906, in response to determining that the first touch andthe second touch failed to occur along a sensing axis, method 1900 mayproceed to 1912 and end. For example, the one axis anti-ghostmeasurement may be not initiated. Instead, the controller may beconfigured to subsequently perform method 900 at 906, where thecontroller may be configured to determine whether the first touch andsecond touch share at least one anti-ghost based on sense signals (e.g.,as generated by sensing cycles). Alternatively or additionally, in someembodiments, the one axis anti-ghost method may be used as the primary,rather than a secondary, method of associating touches; in this casedecision step 1906 of method 1900 may be eliminated so that step 1904proceeds unconditionally to decision step 1908.

Multi-Sensing Axis Touch Sensors

In some embodiments, a touch sensor may include more than two (e.g., XY)sensing axes. Additional sensing axes (e.g., XYU, XYUV, etc.) may allowfor reliable anti-ghost overlap resolution for additional (e.g., greaterthan two) concurrent touches (e.g., such as when a first touch and asecond touch are along a first sensing axis and the first touch and athird touch are along a second sensing axis). Furthermore, two touchesgenerated by a common touch entity will share at least one (e.g.,non-overlapping) anti-ghost even when the two touches are along asensing axis.

FIG. 21 shows an example XYU sensing array 2100 in accordance with someembodiments. XYU sensing array 2100 may include X axis electrodes 2104,Y axis electrodes 2102 and U axis electrodes 2106. X axis electrodes2104 may define an X sensing axis, Y axis electrodes 2102 may define a Ysensing axis, and U axis electrodes 2106 may define a U sensing axis ofXYU sensing array 2100. For two concurrent touches 2108 and 2110 from acommon touch entity along the X sensing axis, touches 2108 and 2110would only share overlapping anti-ghosts if the sensing array were an XYsensing array (e.g., as shown in FIG. 13 ). However, with the additionalU sensing axis, anti-ghosts 2112 and 2114 can be detected by thecontroller and a determination can be made that touches 2108 and 2110share (e.g., non-overlapping) anti-ghosts 2112 and 2114 at theintersections of projections of touches 2108 and 2110 perpendicular to Xand U sensing axis directions. Here, anti-ghosts 2112 and 2114 may be XUanti-ghosts.

FIG. 22 shows an example XYU touch sensor 2200 in accordance with someembodiments. XYU touch sensor 2200 is a three sensing axis touch sensorconfigured to perform (two axis) anti-ghost measurements. XYU touchsensor 2200 includes XYU sensing array 2202 including X axis electrodes2206, Y axis electrodes 2204, and U axis electrodes 2208. XYU touchsensor 2200 further includes drive electronics 2208 connected with Yaxis electrodes 2204 (e.g., drive electrodes), sense electronics 2210connected with X axis electrodes 2206 (e.g., sense electrodes), anddrive and sense electronics 2212 connected with U axis electrodes 2208(e.g., drive and sense electrodes).

Drive and sense electronics 2212 can be configured to enable measurementof capacitance and, thus, detect anti-ghosts at XY, XU and YU electrodeintersections. For example, if Y axis electrodes 2204 operates only inthe drive mode and X axis electrodes 2206 operate only in the sensemode, U axis electrodes 2208 may operate in the drive mode to detect XUanti-ghosts and may operate in the sense mode to detect YU anti-ghosts.As shown, multi-axis touch sensors do not necessarily require drive andsense electronics for each sensing axis to support detection of all oneaxis anti-ghosts. In general, for a multi-axis touch sensor, one sensingaxis may include only drive electronics, one sensing axis may includeonly sense electronics, and the remaining sensing axis may include driveand sense electronics.

FIG. 23 shows an example XYUV sensing array 2300 in accordance with someembodiments. XYUV sensing array 2300 may include X axis electrodes 2304,Y axis electrodes 2302, U axis electrodes 2306, and V axis electrodes2308. X axis electrodes 2304 may define an X sensing axis, Y axiselectrodes 2302 may define a Y sensing axis, U axis electrodes 2306 maydefine a U sensing axis, and V axis electrodes 2308 may define a Vsensing axis. In general, sensing axis orientations are not limited tothe examples shown. For example, a three sensing axis touch sensor isnot limited to the XYU orientation, and may include a more symmetric XUVorientation where there is a 60° angle between the directions of eachsensing axis (e.g., as defined by the sensing array).

In some embodiments, a touch sensor may include more than four sensingaxes. FIG. 21 shows a trend that an increase in the number of sensingaxes may correspond with an increase in number of concurrent touchesthat may be supported without touch entity identification ambiguity(e.g., at least one non-overlapping anti-ghost is shared for each touchpair generated by a common touch entity). For example, two sensing axes(e.g., XY) touch sensor may support one touch without ambiguity notusing one axis anti-ghost measurements and two touches without ambiguityusing one axis anti-ghost measurements, as discussed above in connectionwith FIGS. 18-20 . In another example, a three sensing axes (e.g., XYU)touch sensor may support three touches without ambiguity, regardless ofwhether one axis anti-ghost measurements are used.

Multi-Sensing Axis Sensing Arrays

In some embodiments, a sensing array may include electrode geometriesother than the stripe structures shown in FIG. 1 for X axis electrodes114 and Y axis electrodes 112 of sensing array 104. FIG. 24 shows anexample sensing array 2400 in accordance with some embodiments. Sensingarray 2400 may include polygonal electrodes, with interconnected groupsof electrodes defining the X and Y sensing axis. For example,interconnected electrodes 2402, 2404 and 2406 (e.g., as well as theother electrodes labeled “X”) may define the X sensing axis and may beconnected with drive and/or sense electronics (e.g., as shown in FIGS.17 and 18 ). Similarly, interconnected electrodes 2408, 2410 and 2412(e.g., as well as the other electrodes labeled “Y”) may define the Ysensing axis and may also be connected with drive and/or senseelectronics.

FIG. 25 shows an example XUV sensing array 2500 in accordance with someembodiments. XUV sensing array 2500 may include a first plurality ofelectrodes (e.g., X axis electrodes marked “X”) that define an X sensingaxis, a second plurality of electrodes (e.g., U axis electrodes marked“U”) that define a U sensing axis, and a third plurality of electrodes(e.g., V axis electrodes marked “V”) that define the V sensing axis. Insome embodiments, each of the electrodes may be disposed on a singleelectrode substrate layer (e.g., via disposing ITO to form theelectrodes on a glass or a polymer substrate such as PET).Advantageously, the XUV orientations may be symmetrically oriented with60° angle between the directions of each sensing axis. Alternatively,the pattern of FIG. 25 may be subjected to any two-dimensional lineartransformation to produce another design with different angles betweenthe X, U, and V. For example, transforming the Cartesian coordinates ofthe plane of FIG. 25 with the shear matrix M where Mxx=2/√3, Mxy=0,Myx=1/√3 and Myy=1 would leave the X sensing direction unchanged, orientthe V sensing direction to be in the Y direction, and orient the Udirection at 45° between the X and Y directions, that is transform XUVinto XYU.

XUV sensing array 2500 may include one or more single layer bridges,such as single layer bridge 2502. Alternatively, multiple layer bridgesmay be used to make the desired connections, however to minimizemanufacturing cost by reducing the number of manufacturing steps, singlelayer bridge designs may be preferable. At a single layer bridge, twoelectrodes of the first plurality of electrodes (e.g., X electrodes) maybe electrically connected, two electrodes of the second plurality ofelectrodes (e.g., U electrodes) may be electrically connected, and twoelectrodes of the third plurality of electrodes may be electricallyconnected. FIG. 26 shows a more detailed view of single layer bridge2502 in accordance with some embodiments. At single layer bridge 2502, Xaxis electrodes 2504 and 2506 may be connected with each other viaconductive connection 2602, V axis electrodes 2508 and 2510 may beconnected with each other via conductive connection 2604, and U axiselectrodes 2512 and 2514 may be connected with each other via conductiveconnection 2606.

Electrodes defining different sensing axes may not be interconnected.Rather, single layer bridge 2502 may be configured to isolate electrodesof different sensing axes from conductive contact via one or moreinsulating layers. For example, conductive connection 2602 may beisolated from conductive connections 2604 and 2606 by insulatingmaterial 2610 and 2608, respectively. Furthermore, conductive connection2604 may be isolated from conductive connection 2606 by insulatingmaterial 2612.

In some embodiments, conductive connections 2602, 2604 and 2606 aredisposed such that they do not all intersect at one spatial location, inorder to avoid requiring the manufacturing cost of multiple insulatingmaterial layers to electrically isolate each of conductive connections2602, 2604 and 2606 and the intersection (e.g., connection 2602, firstinsulating material layer, connection 2604, second insulating materiallayer, and connection 2606). Rather, by spatially separating theintersections the conductive connections, a single layer of insulatingmaterial may be used. For example insulating materials 2608, 2610 and2612 may define a thickness of the single layer of insulating material.As such, touch sensor thickness, manufacturing complexity (e.g., numberof layering steps), and production costs may be reduced.

FIG. 27 shows an example method 2700 for manufacturing a single layerbridge performed in accordance with some embodiments. Method 2700 may beperformed, for example, to manufacture a plurality of single layerbridges of a sensing array and is described with reference to singlelayer bridge 2502 shown in FIG. 26 .

Method 2700 may begin at 2702 and proceed to 2704, where a firstconductive connection between a first electrode and a second electrodemay be formed. The first electrode and the second electrode may define afirst sensing axis of a sensing array. For example, conductiveconnection 2602 (e.g., as shown in FIG. 27 ) may be formed between Xaxis electrodes 2504 and 2506 that define the X sensing axis. In someembodiments, the conductive connections (e.g., like the electrodes) maybe formed of ITO disposed on electrode substrate layer (e.g., glass).Furthermore, the conductive connections may be disposed before, after,or in the same ITO placement step as electrodes. In some embodiments,other transparent and electrically conductive materials other than ITOmay be used for the electrodes and/or conductive connections.

At 2706, a partial conductive connection of a third electrode may beformed. The third electrode may define a second sensing axis. Forexample, partial conductive connection 2604 a of conductive connection2604 of V axis electrode 2510 may be formed, where V axis electrode 2510may define the V sensing axis. However, the other portion of conductiveconnection 2604, namely partial conducive connection 2604 b, is not beformed at 2607. In some embodiments, steps 2704 and 2706 may beperformed during one and the same manufacturing step in order tominimize the number of manufacturing steps.

At 2708, a single insulating layer may be formed. The single insulatinglayer may electrically isolate the first conductive connection and thepartial conductive connection of the third electrode, such as from otherconductive connections formed on top of the single insulating layer. Forexample, the single insulating layer may include one or more insulatingmaterials 2608, 2610 and 2612 that may define a thickness of the singlelayer of insulating material. In some embodiments, each of the one ormore insulating materials may be formed in a single placement step.

At 2710, a partial conductive connection of a fourth electrode may beformed. The partial conductive connection of the fourth electrode may beelectrically connected with the partial conductive connection of thethird electrode, thereby forming a second conductive connection betweenthe third electrode and fourth electrode defining the second sensingaxis. For example, partial conductive connection 2604 b of conductiveconnection 2604 of V axis electrode 2508 may be formed such that V axiselectrodes 2508 and 2510 are connected via conductive connection 2604. Vaxis electrodes 2508 and 2510 may define the V sensing axis.

At 2712, a third conductive connection of a fifth electrode and sixthelectrode may be formed. The fifth electrode and the sixth electrodedefining a third sensing axis. For example, conductive connection 2606of U axis electrodes 2512 and 2514 may be formed, where U axiselectrodes 2512 and 2414 define the U sensing axis. Method 2700 may thenproceed to 2714 and end. In some embodiments, steps 2710 and 2712 may beperformed in the same manufacturing step in order to minimize the numberof manufacturing steps.

FIG. 28 shows an example of an XYUV sensing array 2800 in accordancewith some embodiments. XYUV sensing array 2800 may include two electrodesubstrate layers on which XY and UV electrodes may be disposed,respectively. For example, XYUV sensing array 2800 may include topelectrode substrate layer 2802 and bottom electrode substrate layer2804. X axis electrodes and Y axis electrodes (e.g., marked “X” and “Y,”respectively) may be disposed on top electrode substrate layer 2802. Uaxis electrodes and V axis electrodes (e.g., marked “U” and “V,”respectively) may be disposed on bottom electrode substrate layer 2804.

The X axis electrodes and the Y axis electrodes may be interconnected toform the X and Y sensing axis via single layer bridges, such as singlelayer bridge 2806. FIG. 29 shows an example single layer bridge 2806 inaccordance with some embodiments. At single layer bridge 2806, the Xaxis electrodes may be connected via conductive connection 2902 and theY axis electrodes may be connected via conductive connection 2904.Furthermore, conductive connections 2902 and 2904 may be electricallyisolated from each other via insulating material 2906.

FIG. 30 shows a cross sectional view of XYUV sensing array 2800 inaccordance with some embodiments. XY electrodes 2802 may be disposed ontop electrode substrate layer 3002. UV electrodes 2804 may be disposedon bottom electrode substrate layer 3004. Next, electrode substratelayers 2802 and 2804 may be joined, such as by adhesive layer 3006. Insome embodiments, adhesive layer 3006 may be an optically clearadhesive. In some embodiments, XY electrodes and UV electrodes may befabricated on opposite surfaces of a single substrate, which in turn maybe bonded via an adhesive layer to a protective layer of glass orplastic.

In some embodiments, a sensing array with multiple electrode substratelayers may include one or more bordered electrodes. FIG. 31 shows anexample top electrode substrate layer 3100 in accordance with someembodiments. Unlike top electrode substrate layer 2802 (e.g., as shownin FIG. 28 ), top electrode substrate layer 3100 may include borderedelectrodes 3102. Each bordered electrode 3102 may include border region3104 and open (e.g., no ITO or other conductive material) region 3106.Open region 3106 may prevent shielding of a bottom electrode substratelayer (e.g., bottom electrode substrate layer 2804 shown in FIG. 28 )from electrical interaction with touch entities by the top electrodesubstrate layer. FIG. 32 shows an example XYUV sensing array 3200 inaccordance with some embodiments. XYUV sensing array 3200 may includetop electrode substrate layer 3100 (e.g., with bordered electrodes) andbottom electrode substrate layer 2804 (e.g., as shown in FIG. 28 ). Asshow, the UV electrodes of bottom electrode substrate layer 2804 receiveless shielding from touches through the open regions 3106 of borderedelectrodes 3102 (e.g., as shown in FIG. 31 ).

FIG. 33 shows an example XYUV sensing array 3300 in accordance with someembodiments. XYUV sensing array 3300 is an example four sensing axessensing array including electrodes formed on a single electrodesubstrate layer. In FIG. 33 , only one electrode group per axis islabeled. For example, one X axis electrode group may include theelectrodes labeled “X” and may be interconnected (e.g., via bridgesproviding conductive connections) as shown such that the X axiselectrode group defines the X sensing axis. One Y axis electrode groupmay include the electrodes labeled “Y” and may be interconnected (e.g.,via bridges providing conductive connections) as shown such that the Yaxis electrode group defines the Y sensing axis. Similarly, one U axiselectrode group and V axis electrode group that define, respectively,the U and V sensing axis are also shown, although the conductiveconnections are omitted to avoid overcomplicating FIG. 33 . FIG. 34shows the XYUV sensing array 3300 of FIG. 33 , except here, eachelectrode is labeled to illustrate electrode placement for multipleelectrode groups of the X, Y, U and V sensing axis.

In some embodiments, a sensing array may be formed of conductive meshelectrodes rather than electrodes formed of continuous coatings. FIG. 35shows example conductive meshes 3500, 3520, 3540 and 3560 in accordancewith some embodiments. Conductive meshes 3500, 3520, 3540 and 3560 maybe each formed of thin and highly conductive metallic material, such ascopper or silver. The line widths may be sufficiently fine (e.g.,perhaps only a few microns wide) and/or cover such a small fraction ofthe surface area that from a user's perspective the mesh may beperceived as transparent (e.g., even when the metallic material would beotherwise opaque). Furthermore, to electrically isolate neighboringelectrodes, conductive meshes 3500, 3520, 3540 and 3560 may each includedeletion lines (e.g., where trace lines are absent) that define thesensing axis. For example, conductive mesh 3500 may define the Y sensingaxis, conductive mesh 3520 may define the V sensing axis, conductivemesh 3540 may define the X sensing axis, and conductive mesh 3460 maydefine the U sensing axis. Advantageously, the open structure of theconductive meshes may prevent top conductive mesh layers from completelyshielding bottom conductive mesh layers when the conductive meshes aredisposed on top of each other to form a sensing array.

FIG. 36 shows a cross sectional view of an example XYUV sensing array3600 in accordance with some embodiments. XYUV sensing array 3600 mayinclude Y (e.g., Y sensing axis) conductive mesh 3500, V conductive mesh3520, X conductive mesh 3540, and U conductive mesh 3560. Y conductivemesh 3500 and V conductive mesh 3520 may be disposed on opposite sidesof mesh substrate layer 3602, which in some embodiments, may includePET. Similarly, X conductive mesh 3540 and U conductive mesh 3560 may bedisposed on opposite sides of mesh substrate layer 3604. Mesh substratelayers 3602 and 3604 (including their conductive meshes) may be joinedvia adhesive layer 3606, which may be further joined to touch substratelayer 3608 via adhesive layer 3610. In various embodiments, the layeringof the conductive meshes within XYUV sensing array 3600 may bedifferent. For example, the Y and U conductive meshes may be exchangedwithin the layer structure and/or any other two conductive meshes.

Multi-User Multi-Touch Applications

The touch sensors discussed herein may be leveraged in virtually anycontext or embodiment in which multiple users simultaneously operate atouch screen. Advantageously, some embodiments may support multi-touchfunctionality for multiple users at the same time.

FIGS. 37A and 37B show example interactive digital signage 3700 and 3750in accordance with some embodiments. An interactive digital signage mayinclude a display for providing a user interface and touch sensor. Viatouches on the touch sensor, users may be allowed to interact with theuser interface. For example, interactive digital signage 3700 and 3750may be located in a train station in San Francisco for traveler use andmay include an interactive map 3702. As shown in FIG. 37A, in responseto determining that touches 3704 and 3706 do not share an anti-ghost,and therefore, are generated by different touch entities, a multipletouch-entity interaction mode may be initiated. Here, touch 3704indicates Denver on interactive map 3702, and as such, informationregarding train schedules and rates from San Francisco) to Denver mayalso be provided for the benefit of the first user. Concurrently, touch3706 indicates Washington D.C. on interactive map 3702, and as such,information regarding train schedules and rates from San Francisco toWashington D.C. may be provided in response for the benefit of thesecond user.

As shown in FIG. 37B, in response to determining that touches 3704 and3706 share at least one anti-ghost, and therefore, are generated by acommon touch entity (e.g., an individual person), a common touch entityinteraction made may be initiated. For example, the common touch entityinteraction mode may provide multi-touch capability for the common touchentity based on touches 3704 and 3706. Here, because touch 3604 (e.g,placed first) indicates Denver and touch 3606 indicates Washington D.C.,information regarding train schedules and rates from Denver toWashington D.C. may be provided in response.

In some embodiments, a touch sensor and/or application (e.g., forinteraction via the touch sensor) may be configured to identify a userbased on a first touch and to receive touch inputs (e.g., forapplication interaction) via other concurrent touches of the user. FIG.38 shows an example computing device 3800 that may include a touchsensor in accordance with some embodiments. As shown, touch 3802 may beassociated with the same user as touch 3806 (e.g., user 3804) becausetouch 3802 and 3806 share anti-ghosts 3808 and 3810. As such, the lefthand of user 3804 may be used to select the blue virtual paint canselection displayed at touch 3806 while the right hand of user 3804 maybe used to concurrently draw with the blue virtual paint. Similarly,touch 3812 may be associated with the same user as touch 3816 (e.g.,user 3814) because touch 3812 and 3816 share anti-ghosts 3818 and 3820.As such, the left hand of user 3814 may be used to select the redvirtual paint can selection displayed at touch 3816 while the right handof user 3814 may be used to concurrently draw with the red virtualpaint.

Other examples of user touch identification may include a multi-usershopping cart application. For example, the display of an interactivedigital signage may show a number of images and/or icons for items thatcan be purchased. A user may put an item into their shopping cart bytouching a desired item with a first touch (e.g., using hand) andconcurrently touching the user's shopping cart (e.g., icon) with asecond touch (e.g., using the other hand). Advantageously, multipleusers may operate the touch sensor and their touches may be identifiedbased on shared anti-ghosts for concurrent touches without having tosplit the display or touch area into designated areas for each user.

In some embodiments, as discussed above in connection with FIG. 10 , thetouch sensor may be configured to determine whether a first person and asecond person establish and/or discontinue electrically conductivecontact. Such a feature may be leveraged in applications that requireusers to touch each other. For example, an application (e.g., amultiplayer game), may ask two users to shake hands, high five, hug, orotherwise establish electrically conductive contact, which may bedetermined to have been successfully completed upon detecting ananti-ghost and determining it is shared with a first touch and a secondtouch, despite the anti-ghost being previously undetected when the firsttouch and the second touch were first detected.

In some embodiments, the touch sensor may be leveraged in applicationsthat require two people to be present, such as for safety and/orsecurity reasons. For example, the touch controller may be part of abuilding directory interactive digital signage (IDS) application in abuilding with an unsupervised swimming pool with a safety policy that noone is allowed to use the pool alone. In addition to written messagesstating the safety policy on the IDS display and elsewhere, an IDSapplication may go a step further and not give directions and/or accessto the swimming pool until two people simultaneously touch the IDStouchscreen (e.g., at least two touches that do not share anyanti-ghosts). While solo swimmers may be tempted to simultaneously touchwith two or more fingers in an attempt to satisfy the multi-touch IDSapplication, the IDS application can be configured to generate and thendetect anti-ghosts, which may in turn be used to indicate touches fromthe same user (e.g., any two of the touches share at least oneanti-ghost). In another example, an IDS access application with theability to unlock a door (e.g., of a bank, warehouse or other facilitystoring high-value items) may be programmed to do so only if two users(e.g., employees) simultaneously request entry.

In some embodiments, special codes may be used that take advantage ofanti-ghosts, such as for providing added security. FIG. 39 shows anexample interactive digital signage (IDS) 3900 in accordance with someembodiments. For example, a preschool may provide IDS 3900 for allowingadults to check in and check out their children. As students arrive withtheir parents, a log-in application may be running on the IDS system.Each parent-child pair may have their own security code to enter whilethe parent's right hand is holding the child's left hand. The privatesecurity code of one particular parent-child pair may be a five fingertouch in a (e.g., larger adult) left hand pattern in Zone A by theparent simultaneous with a five finger touch in a (e.g., smaller child)right hand pattern in Zone B. In some embodiments, Zone A and Zone B maybe part of a displayed image of various animals and the parent-child'ssecret code could be “while holding hands simultaneously five-fingertouch our favorite animal with our free hand”. More sophisticated andunique codes (e.g., preferably for the adult, not the child) may bepossible by varying the number of required touches in each hand,requiring more spread out or tightly clustered touches, tapping patternsetc. Anti-ghosts may be used to confirm that the parent and child areholding hands while touching, reducing the likelihood of spurious log-indata.

Multi-User Multi-Touch Tracking Using Multiple Touch Sensors

Some embodiments may provide for multiple touch sensors that supportmulti-touch functionality for multiple users at the same time. Formultiple touches occurring concurrently on the different touch sensors,the touch sensors may be configured to determine touches that belong toa common touch entity and initiate a common touch entity interactionmode accordingly for those touches. The touch sensors may also determinethat touches belong to different touch entities and may initiate amulti-touch entity interaction mode. For example, in the multi-touchentity interaction mode, multiple common touch entity interaction modesmay be initiated for two or more users concurrently.

FIGS. 40A and 40B show example sense signal data plots 4000 and 4050,respectively, from multiple touch sensors in accordance with someembodiments. Like FIGS. 3, 5, 7, 8A, and 8B, for example, FIGS. 40A and40B represent tables of entries corresponding to intersections betweendrive and sense electrodes. FIG. 40A shows touch sensors runningasynchronously; FIG. 40B shows touch sensors running synchronously.

FIGS. 40A and 40B include touch sensors 4002, 4004, 4006, and 4008. Inan embodiment, touch sensors 4002, 4004, 4006, and 4008 are each thesame type of touch sensor as touch sensor 100, although in otherembodiments, different sensor types are used. Although FIGS. 40A and 40Bdepict four touch sensors, embodiments of the invention also support anycombination of type or number of touch sensors. For example, embodimentsof the invention support 2, 3, 6, 10, etc. touch sensors.

In FIGS. 40A and 40B, touch sensors 4002, 4004, 4006, and 4008 are incommunication with each other via a shared controller (not shown) thatreceives or transmits sense signals from touch sensors to one another.Alternatively or additionally, touch sensors 4002, 4004, 4006, and 4008can each have their own controller, have a shared controller that is incommunication with the touch sensors' respective controllers, or anycombination thereof.

For clarity of presentation, electrodes in FIGS. 40A and 40B are notshown as numerous small entry boxes as in FIGS. 3, 5 and 7 , but ratherrepresent electrodes as a quasi-continuous horizontal axis andelectrodes as a quasi-continuous vertical axis. Sense signal data plots4000 and 4050 may be generated based on the sense signal data receivedfrom sensing arrays of the respective touch sensors, such as during asensing cycle. Sense signal plots 4000 and 4050 may include backgroundsof the touch sensors representing the baseline mutual capacitancebetween drive and sense electrodes. Touches 4010, 4012, 4014, and 4016may be generated by a first touch entity (e.g., touch entity A) and mayrepresent mutual capacitance values less than the baseline mutualcapacitance. Similarly, touch 4018 may be generated by a second touchentity (e.g., touch entity B) and may also represent mutual capacitancevalues less than the baseline mutual capacitance.

Referring to FIG. 40A, because touches 4010 and 4012 are from a commontouch entity (e.g., touch entity A), circuitry discussed herein, e.g. ashared controller, can be configured to detect an anti-ghost associatedwith any two pairs of touches 4010 and 4012. Upon detecting ananti-ghost associated with a pair of touches from the sense signalsreceived from the sensing arrays, the circuitry may be furtherconfigured to determine that pair of touches “share” an anti-ghost. Forexample, anti-ghost 4020 may be determined to be shared by touches 4010and 4012.

In an embodiment, anti-ghost 4020 may be determined to be shared bytouches 4010 and 4012 by detecting anti-ghost 4020 along a sense lineshared with touch 4012. For example, the electronics of touch sensor4006 can be driving the X electrode indicated by the dashed verticalline running through 4010, and the electronics of touch sensor 4004 canbe driving the X electrode indicated by the vertical dashed line runningthrough anti-ghost 4020. This will result in the anti-ghost signal 4020appearing on the indicated horizontal sense line that associatedelectronics will associate with the position indicated at anti-ghost4020. If the drive signal oscillation of the lower left electronics isin phase with the drive signals of the upper right electronics, thetouch will produce anti-ghost 4020. If the two sets of electronicshappen to be exactly or substantially 180° out of phase, then it may bedetermined that there is a ghost, but not an anti-ghost, at the locationof anti-ghost 4020. More generally, touch sensor 4004 may be subjectedto extra measurable electronic noise or interference when measuringmutual capacitance at the position of anti-ghost 4020. This extrameasurable electronic noise or interference, when detected along thesense line shared with touch 4012, can indicate that touches 4010 and4012 are by a common touch entity.

Because touch sensors 4002, 4004, 4006, and 4008 in FIG. 40A are runningasynchronously, the offset between the driven vertical electrodes of thetwo touches along the sensing line may be random and vary with time.Accordingly, the location of extra electronic noise or interference candrift randomly along the sensing electrode, which is represented by thethin horizontal line passing under touch 4012.

In some embodiments, drive signals from touch sensor 4004 can passthrough the common touch entity to sense electrodes (not shown) in touchsensor 4006 resulting in a measured location of electronic noise orinterference that can drift randomly along a common sense line withtouch 4010, e.g. at a position along horizontal electrodes under thetouch 4010.

Referring to FIG. 40B, because touches 4014 and 4016 are from a commontouch entity (e.g., touch entity A), circuitry discussed herein, e.g. ashared controller, can be configured to detect an anti-ghost associatedwith any two pairs of touches 4014 and 4016. Upon detecting ananti-ghost associated with a pair of touches from the sense signalsreceived from the sensing arrays, the circuitry may be furtherconfigured to determine that pair of touches “share” an anti-ghost. Forexample, anti-ghost 4022 may be determined to be shared by touches 4014and 4016.

In the example of FIG. 40B, touch sensors 4002, 4004, 4006, and 4008 runsynchronously, i.e. corresponding electrodes from the touch sensors areconcurrently driven. For example, when the left most X electrode oftouch sensor 4006 is driven, so is the left most X electrode touchsensors 4002, 4004, and 4008. Although the following will discuss thesituation in which the sensors are driven along the X axis placement,embodiments of the invention support other techniques for mappingelectrodes of the touch sensors to each other. For example, the mappingcan include an offset (e.g. X electrode of touch sensor 4002 correspondsto X+3 electrode of touch sensor 4004), an arbitrary mapping, or anymapping thereof. In an embodiment, drive signals from any combination ofall or some of the touch sensors can be in phase.

In an embodiment, anti-ghost 4022 is determined to be shared by touches4014 and 4016 by detecting anti-ghost 4022 along a sense line sharedwith touch 4014, by detecting anti-ghost 4024 along a sense line sharedwith touch 4016, or both. Touch sensors 4004 and 4006 are synchronizedso that when a line on touch sensor 4004's X axis is driven, acorresponding line on touch sensor 4006 is driven at the same locationon the X axis. For example, FIG. 40B shows a scenario in which one usertouches the touch sensor 4006 at coordinates (X1,Y1), i.e. touch 4014,and another user touches the touch sensor 4004 at coordinates (X2,Y2),i.e. touch 4016. Because the two users are in electrical contact formingtouch entity A, the anti-ghosts will appear and be steady and trueanti-ghosts with opposite signal polarity relative to true touchlocations. Anti-ghost 4022 will appear at location (X2,Y1) of the touchsensor 4006 and anti-ghost 4024 will appear at location (X1,Y2) in touchsensor 4004. In this example, the numerical values of X1, X2, Y1 and Y2are with respect to the local coordinate system of the touch sensorcontaining the touch or anti-ghost.

As shown in FIG. 40B, anti-ghosts may be detected at intersections ofprojections of a first touch of a touch entity on a first touch sensorand the driven line on the first touch sensor corresponding to a drivenline of a second touch on a second touch sensor. For example, anti-ghost4024 may be detected at the intersection of the projection of touch 4016along the X axis and the projection along the Y axis of the linecorresponding to the driven line from touch 4014. Similarly, anti-ghost4022 may be detected at the intersection of the projection of touch 4014along the X axis direction and the projection along the Y axis of theline corresponding to the driven line from touch 4016, which results inanti-ghost 4022.

As shown in sense signal data plot 4050, two touches from differenttouch entities do not share anti-ghosts. For example, no anti-ghost maybe detected at intersection 4026 of projections along sX axis from touch4018 (from touch entity B) and projections along Y axis along the drivenline on touch sensor 4004 corresponding to the driven line of touch 4014(from touch entity A). Similarly, there is no anti-ghost detected ontouch sensor 4006 at the intersection 4028 of projections along X axisof touch 4014 (from touch entity A) and projections along Y axis alongthe driven line on touch sensor 4006 corresponding to the driven line oftouch 4018 (from touch entity B).

In an embodiment, using appropriate synchronization methods, theprinciples of multi-user anti-ghost PCAP can be extended from singletouch sensor to tiled arrays of touch sensors. The presence or absenceof anti-ghosts at predictable locations can be used to determine whenpairs of touches electrically connected. Further, the principles aboveare independent of the geometry of the tiling. The tiling “array” couldbe a horizontal row of touch sensors, a vertical row of touch sensors,or a “tiling” can be a set of touch sensors placed in any configuration,e.g. at arbitrary or random locations on the walls of room.

FIG. 41 shows an example method 4100 for providing multi-usermulti-touch functionality using multiple touch sensors based onanti-ghosts performed in accordance with some embodiments. Method 4100may be performed to leverage the anti-ghost effect discussed above. Insome embodiments, method 4100 may be performed by a shared controllerand/or other suitably configured circuitry, such as controller 108 oftouch sensor 100 shown in FIG. 1 .

Method 4100 may begin at 4102 and proceed to 4104, where the sharedcontroller may be configured to receive a first sense signal from afirst sensing array. The first sense signal may indicate a first touchon a first touch surface of a first touch substrate, such as touchsurface 110 of touch substrate 102 of touch sensor 4004. At 4106, theshared controller may be configured to receive a second sense signalfrom a second sensing array. The second sense signal may indicate asecond touch occurring concurrently to the first touch on a second touchsurface of a second touch substrate, such as touch surface 110 of touchsubstrate 102 of touch sensor 4006.

In some embodiments, the sense signals may represent sense signal dataacquired during sensing cycles of touch sensors 4004 and 4006. As such,the first touch and the second touch may occur “concurrently” on theirrespective touch surfaces when present during a single sensing cycle.For example, the first touch and the second touch may first occur (e.g.,begin) simultaneously and may be maintained for the single sensingcycle. Furthermore, the first touch and the second touch may occur“concurrently” despite beginning at separate times. For example, thefirst touch may occur (e.g. begin) on the first touch surface prior tothe second touch on the second touch surface and may be maintained onthe first touch surface such that the first touch is concurrent with thesecond touch (e.g., for the single sensing cycle).

At 4108, the shared controller may be configured to determine whetherthe first touch and the second touch share at least one anti-ghost basedon the first and second sense signals. For example, and as discussedabove in connection with FIGS. 40A and 40B (e.g., touches 4010 and 4012of FIG. 40A or touches 4014 and 4016 of FIG. 40B), the shared controllermay be configured to determine that the first touch and the second touchshare the at least one anti-ghost when the at least one anti-ghost ispresent at the intersection of a sense line shared with a touch and adriven line corresponding to a touch from another touch sensor (e.g. atanti-ghosts 4022 and 4024). Similarly, the shared controller may beconfigured to determine that the first touch and the second touch failto share the at least one anti-ghost when no anti-ghost is present atthe intersection of a sense line shared with a touch and a driven linecorresponding to a touch from another touch sensor (e.g. intersections4026 and 4028 of FIG. 40B).

In response to the controller determining that the first touch and thesecond touch share the at least one anti-ghost, method 4100 may proceedto 4110, where the controller may be configured to associate the firsttouch and the second touch with a common touch entity. As discussedabove, the common touch entity may be an individual person or may be twoor more people in electrically conductive contact.

At 4112, the controller may be configured to enable a common touchentity interaction mode. For example, the first touch and the secondtouch may be used to determine a multi-touch capability of the sharedcontroller such as pinch to zoom, two-finger scrolling, secondaryselect, and/or any other suitable multi-touch input. Method 4100 maythen proceed to 4114 and end.

Returning to 4108, in response to determining that the first touch andthe second touch fail to share the at least one anti-ghost (e.g., do notshare any anti-ghosts), method 4100 may proceed to 4116, where theshared controller may be configured to associate the first touch with afirst touch entity and the second touch with a second touch entitydifferent from the first touch entity. For example, the first touchentity may be a first person and the second touch entity may be a secondperson.

At 4118, the controller may be configured to enable a multipletouch-entity interaction mode. For example, the first touch and thesecond touch may each be used to determine separate single touchcapability of shared controller. Although method 4100 is discussed withrespect to two touches, it is appreciated that more than two touches maybe detected in the sense signals. For example, a third touch may bedetected and share at least one anti-ghost with the first touch and noanti-ghosts with the second touch. Here, common touch entity interactionmode may be enabled for the first and third touch and multipletouch-entity interaction mode be enabled for the second touch and thecombination of the first touch and the third touch. In that sense, amultiple touch-entity interaction mode may include two or more separatecommon touch entity interaction modes. Method 4100 may then end at 4114.

In an embodiment, one or more techniques for monitoring the continuityof anti-ghosts are used with multiple touch sensors that supportmulti-touch functionality for multiple users. For example, method 1400can be executed to determine, at least partially, whether a second touchbelongs to the same touch entity as the first touch if it is not readilydiscernable two touches of a common touch entity share at least oneanti-ghost when the two touches first become concurrent on the touchsurface, such as but not limited to when multiple anti-ghosts appear intiled touch sensors running asynchronously. In some embodiments, method1400 may be performed by a controller and/or other suitably configuredcircuitry, such as a shared controller or controller 108 of touch sensor100 shown in FIG. 1 .

In an embodiment, one or more techniques for providing multi-usermulti-touch functionality based on signal strength of touches are usedwith multiple touch sensors that support multi-touch functionality formultiple users. For example, method 1500 can be executed to, at leastpartially, resolve the detection of touches associated with the sametouch entity despite not detecting anti-ghosts due to the anti-ghostsoverlapping with the touches or not being able to determine that ananti-ghost corresponds to which of one or more touches. For example,method 1500 may be helpful when a first touch occurs prior to a secondtouch and is maintained on the touch surface such that the first touchis concurrent with the second touch. Independent of whether there is apotential anti-ghost overlap or not, the method 1500 may be performed todetermine whether or not the second touch belongs to the same touchentity as the first touch. In that sense, method 1500 may be performedin response to the second touch being determined as being along a commonsensing axis direction as the first touch and/or when the first touchoccurs prior to the second touch regardless of whether the first touchand the second touch are along a common sensing axis. In someembodiments, like other methods discussed herein, method 1500 may beperformed by a controller and/or other suitably configured circuitry,such as a shared controller or controller 108 of touch sensor 100 shownin FIG. 1 .

Interactions Between Multiple Touch Entities

Some embodiments may provide for one or more touch sensors that supportmulti-touch interactions between multiple users at the same time. Formultiple touches occurring concurrently on the same or different touchsensors, the one or more touch sensors may be configured to determinethat multiple touch entities form a common touch entity and initiate anevent for those interactions.

FIG. 42 shows an example method 4200 for responding to multi-usermulti-touch interactions between multiple touch entities performed inaccordance with some embodiments. Method 4200 may be performed toleverage the anti-ghost effect discussed above. In some embodiments,method 4200 may be performed by a shared controller and/or othersuitably configured circuitry, such as controller 108 of touch sensor100 shown in FIG. 1 .

Method 4200 may begin at 4202 and proceed to 4204, where a sharedcontroller may be configured to receive a first sense signal indicatinga first touch attributed to a first touch entity. The first touch can befrom a first touch surface of a first touch substrate, such as touchsurface 110 of touch substrate 102 of touch sensor 100 or of touchsensor 4004.

At 4206, the shared controller may be configured to receive a secondsense signal indicating a second touch attributed to a second touchentity. The second touch may occur concurrently to the first touch onthe same or a different touch surface, such as touch surface 110 oftouch substrate 102 of touch sensor 100 or touch sensor 4006.

In some embodiments, the sense signals may represent sense signal dataacquired during sensing cycles of touch sensors. As such, the firsttouch and the second touch may occur “concurrently” on their respectivetouch surfaces when present during a single sensing cycle. For example,the first touch and the second touch may first occur (e.g., begin)simultaneously and may be maintained for the single sensing cycle.Furthermore, the first touch and the second touch may occur“concurrently” despite beginning at separate times. For example, thefirst touch may occur (e.g. begin) on the first touch surface prior tothe second touch on the second touch surface and may be maintained onthe first touch surface such that the first touch is concurrent with thesecond touch (e.g., for the single sensing cycle).

At 4208, the shared controller may be configured to determine whetherthe first touch entity and the second touch entity form a common touchentity. The first touch entity and the second touch entity can bedetermined to form a common touch entity using any approach, such as anyof the techniques discussed herein, but not limited thereto. Forexample, the first and second touch entities can be determined to form acommon touch entity based on the presence or absence of anti-ghosts, thetiming of touches, sensed signal strength of touches, or any combinationthereof.

In response to the controller determining that the first touch entityand the second touch entity form a common touch entity, method 4200 mayproceed to 4210, where the controller may be configured to initiate anevent. Method 4200 may then proceed to 4212 and end.

In some embodiments, the event comprises transferring a virtual objectfrom the first touch entity to the second touch entity. The followingprovides non-limiting examples of transferring a virtual object form thefirst touch entity to the second touch entity.

As an example, the first touch entity and second touch entity can beplaying a multiplayer game, such as soccer. In the game, the first touchentity may be represented by an avatar, e.g. a first soccer player, andthe second touch entity may be represented by another avatar, e.g. asecond soccer player. Each touch entity may control the avatar bytouching some control area, e.g. a portion of a touch screen or theavatar on the touch screen. The first touch entity can initiatetransferring an in game object, e.g. passing a soccer ball, to thesecond touch entity by touching the second touch entity, e.g. a tap onthe shoulder with the first touch entity's free hand. When a controllerdetermines that the first touch entity and the second touch entity forma common touch entity, the controller can send a signal to the game toinitiate the transfer. For example, in the game this translates to thefirst avatar attempting to pass the soccer ball to the second avatar.Although soccer is used in this example, embodiments of the inventionsupport any game, such as football, hockey, etc.

As another example, the first touch entity and second touch entity canbe interacting with data in a GUI (graphical user interface), such asdifferent applications in a windowing system. In the GUI, the firsttouch entity may be highlighting data in a spreadsheet application usinga first touch. The second touch entity may be highlighting a data entryfield in a second application using the second touch. The first touchentity can initiate transferring the data from the spreadsheet to thesecond application by touching the second touch entity, e.g. by tappingthe second touch entity on the shoulder. When a controller determinesthat the first touch entity and the second touch entity form a commontouch entity, the controller can send a signal to the GUI to initiatethe transfer. As a result, the highlighted data is copied from thespreadsheet application to the second application. In this example, theformed common touch entity may be temporary and revert to separate firstand second touch entities when the triggered actions are completed andelectrical contact between the first and second touch entities isterminated.

In some embodiments, the event comprises assigning a designation of thefirst touch entity to the second touch entity. The designation canindicate that the entities are a part of the same team, unit,organization, side, etc. For example, a user on a first team of a gamecan tag a second user to indicated that the second user is on the firstteam.

In some embodiments, the shared controller may be configured todetermine that the first touch entity and the second touch entity havestopped forming a common touch entity based on the first sense signaland second sense signal. The first touch entity and the second touchentity can be determined to have stopped forming a common touch entityusing any approach, such as any of the techniques discussed herein, butnot limited thereto. For example, the first and second touch entitiescan be determined to have stopped forming a common touch entity based onthe presence or absence of anti-ghosts, the timing of touches, sensedsignal strength of touches, or any combination thereof. In response todetermining that the first touch entity and the second touch entity havestopped forming a common touch entity, the shared controller may beconfigured to initiate a second event.

In some embodiments, the second event comprises maintaining anassociation of the first touch entity and the second touch entity afterthe first touch entity and second touch entity separate. Theassociation, like a designation, can indicate that the entities are apart of the same team, unit, organization, side, etc. For example,referring back to the example of assigning a designation, if the firstand second touch entities separate and stop forming a common touchentity, the first and second touch entities can both be designated asmembers of the same team.

In some embodiments, the shared controller may be configured to receivea third sense signal indicating a third touch attributed to a thirdtouch entity. Based on the third sense signal and second sense signal,the shared controller may be configured to determine that the thirdtouch entity and the second touch entity form a second common touchentity. In response to determining that the third touch entity and thesecond touch entity form the second common touch entity, the sharedcontroller may be configured to initiate a third event. The third eventcan include, for example, transferring a virtual object from the secondtouch entity to the third touch entity, assigning a designation of thethird touch entity to the second touch entity, maintaining anassociation of the second touch entity or third touch entity, or anycombination thereof.

In some embodiments, the association of touches is tracked using touchgroup identifiers. A touch group entity identifier may be assigned foreach touch. The touch group entity identifier may be unique. Forexample, the touch group entity identifier may be implemented using aunique 32 bit integer number. The touch group entity identifier may beassigned to one or more touches that belong to a same owner groupidentity. For example, a group of touches that have strong PCAPanti-ghost presence between any two of them, such as touches from one ormore people identified as belonging to a common touch entity, can belongto a same touch group entity. As another example, a single touch whichdoes not have any anti-ghost or might have noise level anti-ghostpresence, such as a single touch from a single touch entity, can haveits own unique touch group entity identification.

In some embodiments, different touch group entities can join to becomeone touch-group-entity by making a new physical contact between at leastone of the members of these different touch group entities. Similarly,when two or more touch entities get separated by removing a physicalcontact, these touch group entities can each become a new touch groupentity. Alternatively, when two or more touch entities are separated byremoving a physical contact, one resulting touch entity may inherit theexisting group entity and the other touch entities may form new groupentities.

In some embodiments, the touch group entity group and its identificationexists while at least one touch that belongs to the group is touchingthe screen. While the touch group entity group exists, the touches thatbelong to the touch group entity can disappear from the group by liftingthose touches from the screen and new touches can be added to the touchgroup entity by additional touches with a strong physical connection tothe touch group entity are made. In some cases, a weak anti-ghostingsignal may be observed with two users in close proximity but notactually touching; this may be due to drive signal transfer between theusers due to a small capacitive coupling between the two users. In anembodiment, if it is desired to only associate the two users when theyare in true physical contact, it may be required that the anti-ghostsignal be sufficiently strong. As it is common in the touch industry torefer to the strength of a touch signal as the “Z” coordinate or valueof the touch, it is natural to associate a Z value with the strength ofan anti-ghost signal. The strength of physical connection is recognized,for example, through the value of the Z value of the anti-ghost pointsbetween touches that exceed a specified threshold.

In some embodiments, each touch can have a unique contact identifierduring the period a touch is made to the screen until the touch islifted from the screen. A touch can also have a touch group entityidentifier. The contact identifier can be given to a newly sensed touch.Touches that are not new but continuous, which can be determined throughexamining the existing valid touch history by one or more techniques,inherits the touch group identifier and contact identifier from theprevious valid touch that it was identified with. New touches that havea strong anti-ghost relationship with any of the touches that with theexisting touch can inherit the touch group identifier of the existingtouch.

In some embodiments, when a touch panel scans the touch input, thecontroller determines the touch groups, and a data structure (e.g. anarray) that identifies the correspondence of touches to touch groups ispassed to next iteration for processing these data. The initialiteration of data processing may include grouping the touch data intotouch groups, e.g. by identifying common touch entities. For example,the data structure can be processed into physical cluster peak touchesby examining anti-ghost presence of two peaks at a time, and if there isa strong physical connection of two touch peaks, they will be clusteredinto the same cluster group; if one of belongs to a physical cluster,the other will inherit the same cluster. If neither of the two toucheshave any cluster associated with, a new physical cluster identification,e.g. touch group entity identifier, can be assigned to these twotouches. A touch peak data that does not have any anti-ghostrelationship will have a new touch group entity identifier assigned toit. After all of the pairs of peaks have been examined, all the toucheswill be clustered.

In some embodiments, in subsequent iterations of processing the datastructure, the data structure from the previous iteration, alone or as apart of a touch history table, can be examined to identify to whichgroup the touch belongs. For example, with an already existing touch, ifa peak is identified with an existing touch, all the touches that belongto the same cluster will inherit this touch group entity identifier. Ifa peak from the same cluster is traced into an existing touch, and ifthe peak one belongs to a different touch group entity in the touchhistory, the earlier created touch group entity identifier (such as asmaller valued integer value) can be assigned as a primary group entity,but the differing group entity identification can be also stored as aprevious touch group entity. This earlier created touch group identifiercan also be assigned to the rest of the cluster. For new touches, a newtouch entry table is generated and put into the touch history table. Fora new cluster, a new touch group entity can be assigned to the touchesin the cluster.

Touch Sensors with Additional Input

In some embodiments, a touch sensor may be combined with another inputsystem, such as a visual input system (e.g. including one or morecameras), which may include three dimensional tracking capabilities. Theother input system may be configured to track the movements of users tofurther associate users with touches. For example, when a first touchand a second touch are not concurrent in time, the first touch and thesecond touch will not share any anti-ghosts regardless of whether theywere generated by a common touch entity or different touch entities. Assuch, a touch sensor that is configured to associate touches based onanti-ghosts may be combined with the other input system to associateconcurrent touches and touches that are separated in time.

FIG. 43 shows an example method 4300 for providing multi-usermulti-touch functionality for non-concurrent touches in accordance withsome embodiments. Method 4300 may be performed to leverage theanti-ghost effect discussed above. In some embodiments, method 4300 maybe performed by a shared controller and/or other suitably configuredcircuitry, such as controller 108 of touch sensor 100 shown in FIG. 1 .Although method 4300 is discussed with respect to using one touchsensor, embodiments of the invention support multiple touch sensors (forexample, four touch sensors as illustrated in FIG. 40 ), as well as incombination with additional input devices (such as one or more cameras).

Method 4300 may begin at 4302 and proceed to 4304, where controller 108may be configured to receive a first entity characteristic correspondingto a first touch. A first sense signal may indicate the first touch on afirst touch surface of a first touch substrate, such as touch surface110 of touch substrate 102 of touch sensor 100. At 4306, the sharedcontroller may be configured to receive a second entity characteristiccorresponding to a second touch. A second sense signal may indicate thesecond touch not occurring concurrently to the first touch on the touchsurface, such as touch surface 110 of touch substrate 102 of touchsensor 100. The first touch and the second touch do not occurconcurrently on their respective touch surfaces when they are both notpresent during any sensing cycles. For example, the first touch canoccur during a first time period, and after the first touch ends, thesecond touch may first occur.

In some embodiments, the entity characteristics may represent dataacquired from one or more sources. An entity characteristic may refer toany attribute that can be used to distinguish one touch entity fromanother. For example, an entity characteristic can include, but is notlimited to, a name, an identifier, the color of an item worn, a face, auser's size, a user's physical capabilities, a user's age, a type ofinput device (e.g., a gloved finger, a bare finger, a stylus, a mobilehandheld computing device, etc.), a number of users, or any combinationthereof. The one or more sources can include, for example, a sensor, acamera, a video, an image source, a RFID reader, a near-fieldcommunication device, a microphone, ultrasonic receiver, such as sonar,an electromagnetic sensor, such as LIDAR, or any combination thereof.

At 4308, the shared controller may be configured to determine whetherthe first touch and the second touch share at least one entitycharacteristic based on the first and second entity characteristics. Forexample, both entity characteristics may be that the user is wearingblue glasses.

In response to the controller determining that the first touch and thesecond touch share the at least one entity characteristic, method 4300may proceed to 4310, where the controller may be configured to associatethe first touch and the second touch with a common touch entity. Asdiscussed above, the common touch entity may be an individual person ormay be two or more people in electrically conductive contact.

At 4312, the controller may be configured to enable a common touchentity interaction mode. For example, the second touch may be used tocontinue an interaction previously engaged in using the first touch,such as drawing a picture. Method 4300 may then proceed to 4314 and end.

Returning to 4308, in response to determining that the first touch andthe second touch fail to share the at least one entity characteristic,method 4300 may proceed to 4316, where the shared controller may beconfigured to associate the first touch with a first touch entity andthe second touch with a second touch entity different from the firsttouch entity. For example, the first touch entity may be a first personand the second touch entity may be a second person.

At 4318, the controller may be configured to enable a multipletouch-entity interaction mode. For example, the first touch and thesecond touch may each be used to determine separate single touchcapability of shared controller. Although method 4300 is discussed withrespect to two touches, it is appreciated that more than two touches maybe detected in the sense signals. For example, a third touch may bedetected and share at least one anti-ghost with the first touch and noanti-ghosts with the second touch. Here, common touch entity interactionmode may be enabled for the first and third touch and multipletouch-entity interaction mode be enabled for the second touch and thecombination of the first touch and the third touch. In that sense, amultiple touch-entity interaction mode may include two or more separatecommon touch entity interaction modes. Method 4300 may then end at 4314.

FIG. 44 shows an example computing device that includes a touch sensor4402 in states 4400, 4440, and 4480 in accordance with some embodiments.States 4400, 4440, and 4480 show an example of method 4300 in practice.However, FIG. 44 is only an example of one instantiation of method 4300,and does not limit method 4300.

In state 4400, touch sensor 4402 associates the two touches of the user4404 and responds with the same color for the user 4404's right and lefthands. User 4404 may have blue glasses, and the color of the trailsdrawn by user 4404 may match the color. The blue glasses are an entitycharacteristic detected by a camera associated with touch sensor 4402.Touch sensor 4402 can associate user 4404's touches based on anti-ghostsdetected on touch sensor 4402. In contrast, touch sensor 4402 maydisplay the touch from user 4406 a different paint color based on, forexample, a lack of anti-ghosts that indicates the touches belong to aseparate touch entity. In this example, user 4406 has red glasses, andthe paint color of the marks left by 4406 is also red (red marks beingrepresented in FIG. 44 as dashed marks).

State 4440 represents a time after state 4400, by which time user 4406had walked away from touch sensor 4402, and user 4404 had moved to theright side of touch sensor 4402. Further, a new user 4408 with purpleglasses has walked up to the left side of touch sensor 4402.

In state 4480, user 4404 starts drawing on touch sensor 4402 again bytouching it. Using the anti-ghost effect alone, touch sensor 4402 maynot be able to determine that the upper right touch during state 4480 isfrom user 4404. However, by tracking the movements of the users with acamera system, the touch sensor 4402 can recognize the touch is fromuser 4404 and provide the paint color consistent with user 4404'searlier touches. The camera system can also recognize that the user 4408is a new user and provide a new paint color accordingly (represented inFIG. 44 by dotted marks). Thus the anti-ghost PCAP system in combinationwith a camera system can not only associate simultaneous touches of auser, but also associate the user's touches that are separated in time.

In an embodiment, touch sensor 4402 is configured to determine a paintcolor for each user. For example, touch sensor 4402 can receive a colorselection from the user, such as by the user selected the color by firsttouching a virtual paint can. Alternatively or additionally, touchsensor 4402 can be configured to select the color based on an entitycharacteristic, such as eye color or shirt color, of the camera image ofthe user.

Increased Anti-Ghost Signal Via Electrode Design

In some embodiments, the strength of the anti-ghost signals are a sideeffect of projected-capacitive touch system design decisions made withother considerations in mind. In other embodiments, projected-capacitivetouch systems may be designed in a way to enhance the strength ofanti-ghost signals relative to touch signals. Electrostatic simulationsmay be used to test various ideas for design alternations.

In some embodiments, reducing the user's capacitance to ground(C_(GROUND)) increases the anti-ghost signal. Techniques to increase theanti-ghost signal can include, for example, reducing thickness orincreasing the dielectric constant of selected dielectric layers, suchas the exterior layer, of the touch sensor stack.

In some embodiments, although touch-to-electrode coupling to both senseand drive lines are important to the anti-ghost signal, only thetouch-to-electrode coupling to sense lines contributes to undesiredelectronic noise. Thus, to improve the strength of anti-ghost signals,sense electrode may be designed to so that user capacitive coupling tosense electrodes (C_(SENSE)) is less than user capacitive coupling todrive electrodes (C_(DRIVE)). This relationship may be represented bythe equation C_(SENSE)<C_(DRIVE).

FIGS. 45A-45C show example sensing arrays 4500, 4510, and 4520,respectively, in accordance with some embodiments. Sensing arrays 4500,4510, and 4520 are designed to improve the strength of anti-ghostsignals by satisfying the relationship C_(SENSE)<C_(DRIVE). In someembodiments, sensing arrays 4500, 4510, or 4520, or any combinationthereof, may be employed in any type of PCAP device, such as thosediscussed herein.

Sensing array 4500 includes sense electrodes 4502 and 4504 and driveelectrodes 4506 and 4508. Although two sense and two drive electrodesare shown, embodiments of the invention support any number orcombination of sense or drive electrodes. By removing centers of thesense electrodes 4502 and 4504, noise from self-capacitive coupling tothe user is reduced.

Sensing array 4510 includes sense electrodes 4512 and 4514 and driveelectrodes 4516 and 4518. Although two sense and two drive electrodesare shown, embodiments of the invention support any number orcombination of sense or drive electrodes. The hypocycloidal shape ofsense electrodes 4512 and 4514 paired with the circular shape of driveelectrodes 4516 and 4518 produce a geometry that leaves touch-inducedmutual capacitance roughly the same due to the similar boundary lengthsbetween the sense and drive electrodes. This arrangement can alsodecrease noise by reducing C_(SENSE), but also leaves the anti-ghostsignal strength roughly the same by compensating the decreased C_(SENSE)by increasing C_(DRIVE) by increasing the area of drive electrodes 4516and 4518.

Sensing array 4520 includes sense electrodes 4522, 4524, and 4526 anddrive electrodes 4528, 4530, and 4532. Although three sense and threedrive electrodes are shown, embodiments of the invention support anynumber or combination of sense or drive electrodes. The design ofsensing array 4520 may be well suited for designs in which the increasein surface area of drive electrodes 4528, 4530, and 4532 relative tosense electrodes 4522, 4524, and 4526 produces the relationshipC_(SENSE)<C_(DRIVE).

In an embodiment, sensing arrays 4500, 4510, and 4520 may each beimplemented with a variety of transparent electrode materials including,for example, indium tin oxide (ITO), silver nanowires, carbon nanotubesas well as metal-mesh.

In some embodiments, the anti-ghosts are measured in the samemutual-capacitance scan as the touches themselves. Alternatively oradditionally, two or more scans may be used, in which at least one scanis configured to collect touch data, such as with the anti-ghostsminimized, and in which at least one other scan is configured to collectanti-ghost data, such as measuring anti-ghosts between parallelelectrodes.

Example Computer System

Various embodiments can be implemented, for example, using one or morewell-known computer systems, such as computer system 4600 shown in FIG.46 . Computer system 4600 can be any well-known computer capable ofperforming the functions described herein, such as computers availablefrom International Business Machines, Apple, Sun, HP, Dell, Sony,Toshiba, etc.

Computer system 4600 includes one or more processors (also calledcentral processing units, or CPUs), such as a processor 4604. Processor4604 is connected to a communication infrastructure or bus 4606.

One or more processors 4604 may each be a graphics processing unit(GPU). In an embodiment, a GPU is a processor that is a specializedelectronic circuit designed to rapidly process mathematically intensiveapplications on electronic devices. The GPU may have a highly parallelstructure that is efficient for parallel processing of large blocks ofdata, such as mathematically intensive data common to computer graphicsapplications, images and videos.

Computer system 4600 also includes user input/output device(s) 4603,such as monitors, keyboards, pointing devices, etc., which communicatewith communication infrastructure 4606 through user input/outputinterface(s) 4602.

Computer system 4600 also includes a main or primary memory 4608, suchas random access memory (RAM). Main memory 4608 may include one or morelevels of cache. Main memory 4608 has stored therein control logic(i.e., computer software) and/or data.

Computer system 4600 may also include one or more secondary storagedevices or memory 4610. Secondary memory 4610 may include, for example,a hard disk drive 4612 and/or a removable storage device or drive 4614.Removable storage drive 4614 may be a floppy disk drive, a magnetic tapedrive, a compact disk drive, an optical storage device, tape backupdevice, and/or any other storage device/drive.

Removable storage drive 4614 may interact with a removable storage unit4618. Removable storage unit 4618 includes a computer usable or readablestorage device having stored thereon computer software (control logic)and/or data. Removable storage unit 4618 may be a floppy disk, magnetictape, compact disk, DVD, optical storage disk, and/any other computerdata storage device. Removable storage drive 4614 reads from and/orwrites to removable storage unit 4618 in a well-known manner.

According to an exemplary embodiment, secondary memory 4610 may includeother means, instrumentalities or other approaches for allowing computerprograms and/or other instructions and/or data to be accessed bycomputer system 4600. Such means, instrumentalities or other approachesmay include, for example, a removable storage unit 4622 and an interface4620. Examples of the removable storage unit 4622 and the interface 4620may include a program cartridge and cartridge interface (such as thatfound in video game devices), a removable memory chip (such as an EPROMor PROM) and associated socket, a memory stick and USB port, a memorycard and associated memory card slot, and/or any other removable storageunit and associated interface.

Computer system 4600 may further include a communication or networkinterface 4624. Communication interface 4624 enables computer system4600 to communicate and interact with any combination of remote devices,remote networks, remote entities, etc. (individually and collectivelyreferenced by reference number 4628). For example, communicationinterface 4624 may allow computer system 4600 to communicate with remotedevices 4628 over communications path 4626, which may be wired and/orwireless, and which may include any combination of LANs, WANs, theInternet, etc. Control logic and/or data may be transmitted to and fromcomputer system 4600 via communication path 4626.

In an embodiment, a tangible apparatus or article of manufacturecomprising a tangible computer useable or readable medium having controllogic (software) stored thereon is also referred to herein as a computerprogram product or program storage device. This includes, but is notlimited to, computer system 4600, main memory 4608, secondary memory4610, and removable storage units 4618 and 4622, as well as tangiblearticles of manufacture embodying any combination of the foregoing. Suchcontrol logic, when executed by one or more data processing devices(such as computer system 4600), causes such data processing devices tooperate as described herein.

Based on the teachings contained in this disclosure, it will be apparentto persons skilled in the relevant art(s) how to make and use theinvention using data processing devices, computer systems and/orcomputer architectures other than that shown in FIG. 46. In particular,embodiments may operate with software, hardware, and/or operating systemimplementations other than those described herein.

CONCLUSION

It is to be appreciated that the Detailed Description section, and notthe Summary and Abstract sections (if any), is intended to be used tointerpret the claims. The Summary and Abstract sections (if any) may setforth one or more but not all exemplary embodiments of the invention ascontemplated by the inventor(s), and thus, are not intended to limit theinvention or the appended claims in any way.

While the invention has been described herein with reference toexemplary embodiments for exemplary fields and applications, it shouldbe understood that the invention is not limited thereto. Otherembodiments and modifications thereto are possible, and are within thescope and spirit of the invention. For example, and without limiting thegenerality of this paragraph, embodiments are not limited to thesoftware, hardware, firmware, and/or entities illustrated in the figuresand/or described herein. Further, embodiments (whether or not explicitlydescribed herein) have significant utility to fields and applicationsbeyond the examples described herein.

Embodiments have been described herein with the aid of functionalbuilding blocks illustrating the implementation of specified functionsand relationships thereof. The boundaries of these functional buildingblocks have been arbitrarily defined herein for the convenience of thedescription. Alternate boundaries can be defined as long as thespecified functions and relationships (or equivalents thereof) areappropriately performed. Also, alternative embodiments may performfunctional blocks, steps, operations, methods, etc. using orderingsdifferent than those described herein.

References herein to “one embodiment,” “an embodiment,” “an exampleembodiment,” or similar phrases, indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it would be within the knowledge of persons skilled in therelevant art(s) to incorporate such feature, structure, orcharacteristic into other embodiments whether or not explicitlymentioned or described herein.

The breadth and scope of the invention should not be limited by any ofthe above-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents.

What is claimed is:
 1. A method for initiating a touch interaction mode for a touch sensor, comprising: receiving a first sense signal indicating a first touch attributed to a first touch entity; receiving a second sense signal indicating a second touch attributed to a second touch entity; responsive to determining that the first touch entity and the second touch entity form a common touch entity: associating the first touch and the second touch with the common touch entity; and enabling a common touch entity interaction mode of the touch sensor; responsive to determining that the first touch entity and the second touch entity do not form the common touch entity: associating the first touch with the first touch entity; associating the second touch with the second touch entity, wherein the second touch entity is different from the first touch entity; enabling a multiple touch interaction mode of the touch sensor; and assigning a first touch group entity identifier to the first touch and a second touch group entity identifier to the second touch entity, wherein the first touch group entity identifier is associated with the first touch entity and the second touch group entity identifier is associated with the second touch entity; receiving a third sense signal indicating a third touch attributed to a third touch entity; and responsive to determining that the first touch entity and the third touch entity form a common touch entity, assigning the first touch group entity identifier to the third touch.
 2. The method of claim 1, wherein determining that the first touch entity and the second touch entity form the common touch entity comprises detecting a presence or absence of anti-ghosts in the first sense signal and the second sense signal.
 3. The method of claim 1, responsive to determining that the first touch entity and the second touch entity form the common touch entity, the method further comprising: assigning a unique touch group entity identifier to the first touch and the second touch entity.
 4. The method of claim 1, wherein the common touch entity interaction mode and the multiple touch interaction mode of the touch sensor are associated with an interactive map application, the method further comprising: displaying map data from the interactive map application in response to the first touch and the second touch.
 5. The method of claim 1, wherein the common touch entity interaction mode and the multiple touch interaction mode of the touch sensor are associated with an interactive painting application, wherein the first touch and the second touch are associated with inputs for controlling the interactive painting application.
 6. A touch sensor comprising: a touch substrate including a touch surface; an sensing array configured to provide sense signals indicating a first touch and a second touch occur concurrently on the touch surface of the touch substrate; and a controller configured to: receive a first sense signal indicating the first touch attributed to a first touch entity; receive a second sense signal indicating the second touch attributed to a second touch entity; responsive to determining that the first touch entity and the second touch entity form a common touch entity: associate the first touch and the second touch with the common touch entity; and enable a common touch entity interaction mode of the touch sensor; responsive to determining that the first touch entity and the second touch entity do not form the common touch entity: associate the first touch with the first touch entity; associate the second touch with the second touch entity, wherein the second touch entity is different from the first touch entity; enable a multiple touch interaction mode of the touch sensor; and assign a first touch group entity identifier to the first touch and a second touch group entity identifier to the second touch entity, wherein the first touch group entity identifier is associated with the first touch entity and the second touch group entity identifier is associated with the second touch entity; receiving a third sense signal indicating a third touch attributed to a third touch entity; responsive to determining that the first touch entity and the third touch entity form a common touch entity, assigning the first touch group entity identifier to the third touch.
 7. The touch sensor of claim 6, wherein determining that the first touch entity and the second touch entity form the common touch entity comprises detecting a presence or absence of anti-ghosts in the first sense signal and the second sense signal.
 8. The touch sensor of claim 6, responsive to determining that the first touch entity and the second touch entity form the common touch entity, the controller further configured to: assign a unique touch group entity identifier to the first touch and the second touch entity.
 9. The touch sensor of claim 6, wherein the common touch entity interaction mode and the multiple touch interaction mode of the touch sensor are associated with an interactive map application, the controller further configured to: display map data from the interactive map application in response to the first touch and the second touch.
 10. The touch sensor of claim 6, wherein the common touch entity interaction mode and the multiple touch interaction mode of the touch sensor are associated with an interactive painting application, wherein the first touch and the second touch are associated with inputs for controlling the interactive painting application.
 11. A non-transitory computer-readable medium storing instructions, wherein the instructions, when executed by a processor, cause the processor of a touch sensor to perform operations comprising: receiving a first sense signal indicating a first touch attributed to a first touch entity; receiving a second sense signal indicating a second touch attributed to a second touch entity; responsive to determining that the first touch entity and the second touch entity form a common touch entity: associating the first touch and the second touch with the common touch entity; and enabling a common touch entity interaction mode of the touch sensor; responsive to determining that the first touch entity and the second touch entity do not form the common touch entity: associating the first touch with the first touch entity; associating the second touch with the second touch entity, wherein the second touch entity is different from the first touch entity; enabling a multiple touch interaction mode of the touch sensor; and assigning a first touch group entity identifier to the first touch and a second touch group entity identifier to the second touch entity, wherein the first touch group entity identifier is associated with the first touch entity and the second touch group entity identifier is associated with the second touch entity; receiving a third sense signal indicating a third touch attributed to a third touch entity; and responsive to determining that the first touch entity and the third touch entity form a common touch entity, assigning the first touch group entity identifier to the third touch.
 12. The non-transitory computer-readable medium of claim 11, wherein determining that the first touch entity and the second touch entity form the common touch entity comprises detecting a presence or absence of anti-ghosts in the first sense signal and the second sense signal.
 13. The non-transitory computer-readable medium of claim 11, responsive to determining that the first touch entity and the second touch entity form the common touch entity, the operations further comprising: assigning a unique touch group entity identifier to the first touch and the second touch entity.
 14. The non-transitory computer-readable medium of claim 11, wherein the common touch entity interaction mode and the multiple touch interaction mode of the touch sensor are associated with an interactive map application, the operations further comprising: displaying map data from the interactive map application in response to the first touch and the second touch. 